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Question 1. A diagram representing the nuclear model of an atom is shown in the image. Name subatomic particles A and B. [2]

Question 2. Find X in the following nuclear equation: ¹²₆C + ⁴₂α → X. [3]

Question 3. Predict the fraction of the initial radioactive isotope remaining in a sample after 30 days if the isotope's half-life is 10 days. [2]

Question 4. Describe how nuclear fission maintains chain reactions. [3]

Question 5. Order the three states of matter according to a decreasing density. [1]

Question 6. A steel block and a lead block are the same size, but the lead block is heavier. Explain the difference in the masses of the blocks. [2]

Question 7. A scientist heats helium gas in a sealed, fixed-volume container from 23°C to 42°C. How would the pressure of the gas change? [1]

Question 8. Why does a glass earring need more energy to heat up than the same mass gold earring? [1]

Question 9. A 3.00 g ice cube melts when supplied with 1002 J of heat. Find the specific latent heat of fusion of water. [3]

Question 10. Explain how pressure varies with an increasing depth within a fluid. [2]

Question 11. Given that the pressure exerted is 200 Pa on an area of 0.5 m², calculate the force exerted on the surface. [1]

Question 12. Explain Newton’s First Law in terms of the formula F = ma. [1]

Question 13. Name the method of estimating the distance travelled from a velocity-time graph in case of non-uniform speed. [1]

Question 14. Rebecca walks 750 m to her grandmother's house. Calculate her average walking speed, given that her journey takes 500 seconds. [2]

Question 15. An object triples its speed in 10 seconds. Given that it has an initial velocity of 1 m/s, calculate the acceleration of the object. [2]

Question 16. How does being tired when driving affect the thinking distance? [1]

Question 17. Thomas pushes a 0.75 kg book off a shelf with a force of 20 N. Given that the book falls with an initial velocity of 1.6 m/s, calculate the contact time between the book and the hand pushing it. [2]

Question 18. State the limit of proportionality of the given material. [1]

Question 19. Use the given graph to calculate the extension of the material when a force of 8 N is applied. [2]

Question 20. Kyle opens their bedroom window by applying a force of 12 N. Given that the moment caused is 6 Nm, calculate the perpendicular distance of the force applied from the pivot. [1]

Question 21. Serkan pushes a weighted sledge forward and then pulls it backwards along the same 25 m path across a rough surface of a gym's functional area. Assuming the frictional force exerted by the ground remains constant at 50 N, calculate the total work done against friction by Serkan during this exercise. [2]

Question 22. Alan stretches an elastic band with a spring constant of 65 N/m, giving it elastic potential energy of 18.28 J. Calculate the extension of the band. [2]

Question 23. Priyanka jogs a few times a week for her cardiovascular health. Given that she has a mass of 65 kg and possesses a kinetic energy of 203.125 J, calculate the velocity at which she is jogging. [2]

Question 24. A light bulb connects in a circuit to a cell. Describe the energy changes that occur in the circuit when it is closed. [3]

Question 25. Ben is comparing the cross section of two double-glazed windows. Why is option A better in cold climates? [2]

Question 26. Define what is meant by power. [1]

Question 27. A lightbulb with an efficiency of 0.75 gets 20 J of electrical energy. Find the energy it lost to the surroundings. [2]

Question 28. Biofuels are said to be carbon-neutral. Explain why. [1]

Question 29. How does sound travel through the air? [1]

Question 30. The wavelength of a wave is 28 m. Calculate the distance between a trough and a consecutive crest. [1]

Question 31. Describe how ultrasound can create an image of a foetus. [3]

Question 32. A wave enters a medium at an angle of 65° and refracts at an angle of 72° to the normal. Compare the densities of the two media. [1]

Question 33. Kayleigh is drinking juice which appears to be orange. Explain why. [1]

Question 34. Predict how far away an object is from the lengths in terms of focal lengths. [1]

Question 35. Amelia received a temperature warning on her phone while hiking with friends. Explain how the device got so hot while being in her pocket. [3]

Question 36. Compare insulators and conductors in producing static electric charge. [2]

Question 37. Compare electrostatic and gravitational forces. [5]

Question 38. Describe the symbols for a resistor and a variable resistor in a circuit diagram. [2]

Question 39. Calculate the potential difference across a 250 Ω resistor if it has a 0.16 A current. [1]

Question 40. Calculate the electric energy of a battery with a potential difference of 12 V and a charge of 3 C. [1]

Question 41. Provide the function of a live wire. [1]

Question 42. A 100 Ω resistor and a 150 Ω resistor connect in series to a 5 V battery. Calculate the total energy dissipated over 10 seconds in both resistors. [3]

Question 43. Explain why the Earth's magnetic North pole is equivalent to the South Pole if the Earth was a bar magnet. [1]

Question 44. State the criterion to use F = BIl for finding the force on a current-carrying conductor in a magnetic field. [1]

Question 45. Name the part of alternator that connects the coil to the rest of the circuit. [1]

Question 46. A transformer comprises 1250 turns in the primary coil and 8720 in the secondary coil. Given that the voltage in the primary coil is 250.0 V, calculate the voltage in the secondary coil. [2]

Question 47. Explain why Pluto is not a planet of the Solar system. [1]

Question 48. An astronaut on a spacewalk accidentally lets go of a tool in low Earth orbit. Describe the motion of the tool after being released. [2]

Question 49. The James Webb Space Telescope has a high clarity of images. Explain why clear pictures are important for studying the early universe. [2]

Question 50. Compare the size of an atom and its nucleus. [1]

Question 51. Define radiation. [1]

Question 52. Scientists are designing a nuclear power generator for a Moon base. What could we say about the half-life of an isotope they should use for power generation? [1]

Question 53. Name two main types of nuclear reactions. [2]

Question 54. Provide a definition for condensing. [1]

Question 55. Find the mass of 62 dm³ of water if it has a density of 1.0 kg/dm³. [2]

Question 56. A gas cylinder contains helium at a pressure of 200 kPa and a volume of 3 m³. The volume changes to 1.5 m³ without any temperature change. Calculate the new pressure of the gas. [2]

Question 57. 57600 J of energy are released when a 12 kg steel block cools down by 10 °C. Calculate the specific heat capacity of steel. [2]

Question 58. Angela boils 0.250 kg of water. Given that the specific latent heat of vaporisation for water is 2260000 J/kg, calculate the energy required for the water to boil. [1]

Question 59. Calculate the pressure at the bottom of a swimming pool of depth 1.8 m, given that the density of water is 1000 kg/m³. [1]

Question 60. Describe the relationship between atmospheric pressure and altitude. [1]

Question 61. State the definition of a force. [1]

Question 62. Ophelia cycles to school to reduce her carbon footprint. Calculate the total distance Ophelia covers with constant speed using the velocity-time graph for her motion. [2]

Question 63. Describe the journey based on the given distance-time graph. [3]

Question 64. The gradient of a velocity-time graph in the first 10 seconds is found to be 1.5 m/s². Given that the velocity at the end of the 10 seconds is 20 m/s, calculate the velocity at 4 seconds. [2]

Question 65. Explain why crumple zones are installed in cars. [1]

Question 66. Lena kicks a 0.4 kg ball for 0.25 seconds to provide it a velocity of 5 m/s. Calculate the force that Lena exerted on the ball. [2]

Question 67. Define what the elastic limit of a material is. [1]

Question 68. Calculate the extension of a spring when a force of 7 N is applied to it, given that it has a spring constant of 14 N/m. [1]

Question 69. State the principle of moments. [1]

Question 70. A lift elevates passengers using a 1650 N force to a 120 m height. Calculate the work done by the lift. [1]

Question 71. A jack-in-a-box spring is compressed by 5 cm when the box is closed. Given that the spring constant is 40 N/m, calculate the elastic potential energy stored in the spring when the box is closed. [1]

Question 72. Define kinetic energy. [1]

Question 73. Peter kicks a football. Name the energy store its kinetic energy converts to after it stops moving. [1]

Question 74. A mechanical lift uses 196 J to lift a 4 kg object. Assuming no frictional forces and a gravitational field strength of 9.8 N/kg, calculate the height through which the box is lifted. [2]

Question 75. An electric motor lifts a 4.5 kg brick to a height of 12 m in 10 seconds. Calculate the motor's power, assuming that the gravitational field strength g = 10 N/kg. [2]

Question 76. A hairdryer uses 15 J of electrical energy.and outputs 3 J of heat. Find its percentage efficiency. [1]

Question 77. Discuss the environmental impact of fossil fuels. [2]

Question 78. Manila has broken her wrist and needs a scan to diagnose it. Explain why X-rays can be used for this scan. [1]

Question 79. Given that 150 cycles of a wave pass through a point on the wave in 3 seconds, calculate the time period of that wave. [1]

Question 80. State the human ear hearing range. [1]

Question 81. A light wave travels through the glass and comes out into the air. Explain what happens to the wave. [3]

Question 82. How does the wavelength relate to the transmission and absorption of waves? [2]

Question 83. Calculate the magnification of a lens, given that the object has a height of 1.2 cm and the image has a height of 18 mm. [2]

Question 84. Which of the following colours of sunglasses would be most suitable for use in hot countries to minimize the amount of heat absorbed by the glasses?

black, green, white, red, blue [1]

Question 85. Find the charge transferred by a 0.45 A current in 160 seconds. [1]

Question 86. Anish sets up a uniform electric field between two parallel plates connected to a power source. Suggest a method to determine which plate has a positive charge. [2]

Question 87. Design an experiment to investigate the current-voltage characteristics of a diode. [4]

Question 88. A 2500 Ω lamp connects to an ammeter that reads 1.50 A. Find the voltage applied to the lamp. [1]

Question 89. Define potential difference. [1]

Question 90. Provide an advantage and a disadvantage of using high voltage. [2]

Question 91. Peter set up a circuit with a 12 V power supply, and a resistor with a resistance of 4.0 Ω. Calculate the power dissipation in the resistor. [2]

Question 92. Describe an induced magnet. [1]

Question 93. Paula places an 80 cm wire in a 1.25 T magnetic field. A current of magnitude 3 A flows through the wire. Given that the whole wire lies in the magnetic field, calculate the magnitude of the force the wire feels. [2]

Question 94. Lola is holding a bar magnet. Jack moves a coil of wire near the magnet. Explain what happens. [2]

Question 95. What type of transformer has fewer turns in its secondary coil? [1]

Question 96. Describe the Moon. [2]

Question 97. A satellite goes from a lower orbit to a higher orbit around Earth. Predict the change in the satellite's motion. [2]

Question 98. Define red-shift in the context of Big Bang theory. [2]

Question 99. Determine the relative atomic mass of the atom shown in the diagram correct to 2 significant figures. [1]

Question 100. Peter has an idea of using irradiation to disinfect plastic food packaging. Discuss the suitability of this approach. [2]

Answer 1. A diagram representing the nuclear model of an atom is shown in the image. Name subatomic particles A and B. [2]

According to the nuclear model an atom consists of a nucleus that is approximately 10,000 times smaller than the atom itself and shells of electrons surrounding the nucleus.

[1 mark] A = electron
[1 mark] B = proton

Answer 2. Find X in the following nuclear equation: ¹²₆C + ⁴₂α → X. [3]

Carbon-12 (¹²C) joins an alpha particle (⁴₂α) and turns into a different element. The mass number of ¹²C is 12, and the mass number of the alpha particle is 4. The sum of these numbers is 16, which matches the mass number of oxygen-16 (¹⁶₈O). Therefore, X is ¹⁶₈O.

[3 marks] ¹⁶₈O
[1 mark] O
[1 mark] 16 as the mass number
[1 mark] 8 as the atomic number

Answer 3. Predict the fraction of the initial radioactive isotope remaining in a sample after 30 days if the isotope's half-life is 10 days. [2]

The fraction of the initial radioactive isotope remaining after 30 days would be 0.5 × 0.5 × 0.5 = 1/8 or 12.5%.

[2 marks] 12.5% or 0.125
[1 mark] 3

Answer 4. Describe how nuclear fission maintains chain reactions. [3]

During fission, a heavy nucleus splits into two smaller nuclei. This reaction often starts after a neutron absorption. Fission releases a significant amount of energy and more neutrons. They can continue the process in a chain reaction. Fission requires a heavy element like uranium or plutonium and a neutron.

[1 mark] neutron absorption
[1 mark] nucleus splitting
[1 mark] neutron release

Answer 5. Order the three states of matter according to a decreasing density. [1]

Generally, solids are the most dense, liquids are less dense, and gases are the least dense. This is because gas particles are furthest away from each other, resulting in the least mass per the same volume.

solid, liquid, gas

Answer 6. A steel block and a lead block are the same size, but the lead block is heavier. Explain the difference in the masses of the blocks. [2]

The key to understanding why the lead block is heavier than the steel block, despite being the same size, lies in the concept of density. Density represents the relationship between an object's mass and the space it occupies. In other words, it measures how much stuff is in a certain volume. In this case, lead and steel have different densities. Lead has a higher density than steel, meaning it has more mass packed into the same volume. Therefore, a lead block of the same size as a steel block will have more mass and, as a result, will be heavier.

[1 mark] higher density of lead
[1 mark] more mass in same volume

Answer 7. A scientist heats helium gas in a sealed, fixed-volume container from 23°C to 42°C. How would the pressure of the gas change? [1]

When a scientist heats helium gas, the kinetic energy of helium increases. Particles then move faster and collide more frequently against the container walls. As a result, the pressure inside the container increases.

[1 mark] higher pressure

Answer 8. Why does a glass earring need more energy to heat up than the same mass gold earring? [1]

Specific heat capacity is the energy required by an object of mass 1 kg for its temperature to increase by 1°C. Since the specific heat capacity of glass is higher, it requires more energy for its temperature to rise than gold.

higher specific heat capacity

Answer 9. A 3.00 g ice cube melts when supplied with 1002 J of heat. Find the specific latent heat of fusion of water. [3]

1 kg = 1000 g
3.00 g = 3.00 ÷ 1000 kg = 0.00300 kg

Q = ml
1002 = 0.00300 × l
l = 1002 ÷ 0.00300 = 3.34 × 10⁵ J/kg

[3 marks] 3.34 × 10⁵ J/kg
[2 marks only] 3.34 × 10⁵ or 1002 = 0.00300 × l
[1 mark] 0.00300 or 0.003

Answer 10. Explain how pressure varies with an increasing depth within a fluid. [2]

The deeper into a fluid one goes, the greater the pressure gets. This is because the height of the column of fluid lying above the point increases. Thus, the weight of the fluid column acting on the point increases.

[1 mark] greater weight
[1 mark] greater pressure

Answer 11. Given that the pressure exerted is 200 Pa on an area of 0.5 m², calculate the force exerted on the surface. [1]

P = F/A
200 Pa = F ÷ 0.5 m²
F = 200 × 0.5 = 100 N

100 N

Answer 12. Explain Newton’s First Law in terms of the formula F = ma. [1]

Newton’s First Law states that a body will remain at equilibrium unless it is acted upon by an external resultant force. When there is no external force, F = 0, therefore since F = ma and an object has mass, a = 0. Therefore, the object will remain in equilibrium.

F = 0, so a = 0.

Answer 13. Name the method of estimating the distance travelled from a velocity-time graph in case of non-uniform speed. [1]

The area under a velocity-time graph is the distance travelled by an object. The area can be approximated by counting squares.

counting squares under graph

Answer 14. Rebecca walks 750 m to her grandmother's house. Calculate her average walking speed, given that her journey takes 500 seconds. [2]

speed = distance ÷ time
speed = 750 ÷ 500
speed = 1.5 m/s

[2 marks] 1.5 m/s
[1 mark] 1.5 or 750 ÷ 500

Answer 15. An object triples its speed in 10 seconds. Given that it has an initial velocity of 1 m/s, calculate the acceleration of the object. [2]

v = u + at
3 × 1 = 1 + a × 10
a = 0.2 m/s²

[2 marks] 0.2 m/s²
[1 mark] 0.2 or 3 × 1 = 1 + a × 10

Answer 16. How does being tired when driving affect the thinking distance? [1]

When drivers are tired, they will likely take longer to react to a dangerous situation. Thus, it will take longer for them to apply the brakes, and their thinking distance will increase.

increased

Answer 17. Thomas pushes a 0.75 kg book off a shelf with a force of 20 N. Given that the book falls with an initial velocity of 1.6 m/s, calculate the contact time between the book and the hand pushing it. [2]

change in momentum = 0.75 kg × 1.6 m/s = 1.2 kgm/s
force = change in momentum ÷ time
time = change in momentum ÷ force
time = 1.2 kgm/s ÷ 20 N = 0.06 s

[2 marks] 0.06 s
[1 mark] 0.06 or 1.2

Answer 18. State the limit of proportionality of the given material. [1]

The limit of proportionality is the point after which the relationship between force and extension becomes non-linear. For this material, it is 0.8 m.

0.8 m

Answer 19. Use the given graph to calculate the extension of the material when a force of 8 N is applied. [2]

The new force is 8 N ÷ 4 N = 2 times greater. Assuming that the straight line continues until 8 N, according to Hooke's law, doubling the applied force should double the extension: 0.15 m × 2 = 0.3 m.

[2 marks] 0.3 m
[1 mark] 2 or 30

Answer 20. Kyle opens their bedroom window by applying a force of 12 N. Given that the moment caused is 6 Nm, calculate the perpendicular distance of the force applied from the pivot. [1]

M = Fd
6 = 12 × d
d = 6 ÷ 12 = 0.5 m

0.5 m

Answer 21. Serkan pushes a weighted sledge forward and then pulls it backwards along the same 25 m path across a rough surface of a gym's functional area. Assuming the frictional force exerted by the ground remains constant at 50 N, calculate the total work done against friction by Serkan during this exercise. [2]

total distance = 25 m × 2 = 50 m

W = Fd
W = 50 m × 50 N
W = 2500 J

[2 marks] 2500 J
[1 mark] 2500 or 1250

Answer 22. Alan stretches an elastic band with a spring constant of 65 N/m, giving it elastic potential energy of 18.28 J. Calculate the extension of the band. [2]

E = 0.5ke²
18.28 = 0.5 × 65 × e²
e = √(18.28 ÷ (0.5 × 65)) = 0.75 m (2 s. f.)

[2 marks] 0.75 m
[1 mark] 0.75 or 18.28 = 0.5 × 65 × e²

Answer 23. Priyanka jogs a few times a week for her cardiovascular health. Given that she has a mass of 65 kg and possesses a kinetic energy of 203.125 J, calculate the velocity at which she is jogging. [2]

E = 0.5mv²
203.125 = 0.5 × 65 × v²
v = √203.125 ÷ (0.5 × 65)) = 2.5 m/s

[2 marks] 2.5 m/s
[1 mark] 2.5 or 203.125 = 0.5 × 65 × v²

Answer 24. A light bulb connects in a circuit to a cell. Describe the energy changes that occur in the circuit when it is closed. [3]

When the circuit is closed, the chemical energy of the battery will be transferred into electrical energy, as the electrons will flow through the circuit, and light energy, as the bulb lights up. Some of the chemical energy will also be transferred into heat energy as the temperature of the light bulb rises.

[1 mark] chemical energy →
[1 mark] → electrical energy →
[1 mark] → light/heat energy

Answer 25. Ben is comparing the cross section of two double-glazed windows. Why is option A better in cold climates? [2]

Option A is thicker. Thus, option A will be more effective in reducing thermal conductivity.

[1 mark] thicker
[1 mark] better insulator

Answer 26. Define what is meant by power. [1]

Power is the rate at which an object does work.

rate of work done

Answer 27. A lightbulb with an efficiency of 0.75 gets 20 J of electrical energy. Find the energy it lost to the surroundings. [2]

efficiency = useful energy ÷ total energy
useful energy = efficiency × total energy
useful energy = 0.75 × 20 J = 15 J
energy lost = 20 J − 15 J = 5 J

[2 marks] 5 J
[1 mark] 5 or 15 or 0.25

Answer 28. Biofuels are said to be carbon-neutral. Explain why. [1]

Biofuels are considered to be carbon-neutral, since they absorb carbon dioxide during their lifecycle, while also releasing carbon dioxide when they are burned.

They absorb and release carbon dioxide.

Answer 29. How does sound travel through the air? [1]

Sound waves vibrate as they travel, causing air particles to vibrate.

vibrating air particles

Answer 30. The wavelength of a wave is 28 m. Calculate the distance between a trough and a consecutive crest. [1]

The wavelength of a wave is the distance between two equal points on consecutive cycles of the wave. Therefore, the distance between a crest and a trough is half that of the wavelength; 28 m ÷ 2 = 14 m.

14 m

Answer 31. Describe how ultrasound can create an image of a foetus. [3]

Ultrasound waves are emitted from a source into the stomach of the pregnant person. When ultrasound waves reach the object's boundary, a source emits into them, and some waves will be reflected. The time taken for the reflected wave to reach a detector after being emitted from the source is measured. Using the speed of sound, the distance the wave travels through can be calculated. These distance calculations can be used to form images.

[1 mark] reflected waves
[1 mark] recording time
[1 mark] calculating distance

Answer 32. A wave enters a medium at an angle of 65° and refracts at an angle of 72° to the normal. Compare the densities of the two media. [1]

When the wave enters a less dense medium at an angle to the normal, its speed increases and it bends away from the normal. Since the angle of refraction is bigger than the angle of incidence, the ray has bent away from the normal, and the initial medium is more dense.

Initial medium is denser.

Answer 33. Kayleigh is drinking juice which appears to be orange. Explain why. [1]

The juice in Kayleigh’s glass absorbs all light colours except for orange. The orange light rays are reflected, making the juice appear orange.

It absorbs all light except orange.

Answer 34. Predict how far away an object is from the lengths in terms of focal lengths. [1]

A ray is drawn horizontally from the object to the lens, diverges upwards, and an imaginary extension is drawn to go through the principal focus in front of the lens. A second ray is drawn to go through the centre of the lens. The image is formed at the point at which the two rays meet. The ray diagram is for a concave lens, where the object is between one and two focal lengths away from the lens.

one to two focal lengths

Answer 35. Amelia received a temperature warning on her phone while hiking with friends. Explain how the device got so hot while being in her pocket. [3]

Amelia's phone likely got hot due to the combined effects of the device's internal components working hard and the insulation provided by her pocket. As smartphones operate, especially when running GPS, camera, or other intensive applications, they generate heat. The tight space in Amelia's pocket traps this heat, preventing it from efficiently radiating away, similar to how a black body would absorb and re-emit radiation, leading to an increase in the device's temperature.

[1 mark] internal heat
[1 mark] insulation by pocket
[1 mark] heat from environment

Answer 36. Compare insulators and conductors in producing static electric charge. [2]

Insulators and conductors differ in their ability to produce static electric charge. Insulators, such as rubber or plastic, do not allow electric charge to flow, resulting in charge build-up on their surfaces when rubbed together. Conductors, such as metals, allow electric charge to flow through them, making it more difficult for static charge to build up on their surfaces.

[1 mark] insulators: charge build-up
[1 mark] conductors: charge flow

Answer 37. Compare electrostatic and gravitational forces. [5]

Electrostatic forces arise from charges and can be attractive or repulsive, depending on the charges of the interacting particles. Gravitational forces arise from mass and are always attractive.

[1 mark] electrostatic: attractive, repulsive
[1 mark] gravitational: always attractive
[1 mark] electrostatic: from charges
[1 mark] gravitational: from masses
[1 mark] both: non-contact

Answer 38. Describe the symbols for a resistor and a variable resistor in a circuit diagram. [2]

A resistor in a circuit diagram has a rectangle symbol. It opposes current flow in the circuit, dissipating electrical energy as heat. A variable resistor has a similar rectangle symbol with an arrow pointing diagonally through it. The purpose of a variable resistor is to adjust the resistance in the circuit, allowing control over the current flow and the amount of energy dissipated.

[1 mark] resistor: rectangle
[1 mark] variable resistor: rectangle with diagonal arrow

Answer 39. Calculate the potential difference across a 250 Ω resistor if it has a 0.16 A current. [1]

Using Ohm's law (V = I × R), we can find the potential difference (V) across the resistor. In this case, I = 0.16 A and R = 250 Ω. V = 0.16 A × 250 Ω = 40 V. The potential difference across the resistor is 40 volts.

40 V

Answer 40. Calculate the electric energy of a battery with a potential difference of 12 V and a charge of 3 C. [1]

To calculate the electric energy (W) of a battery with a potential difference of 12 V and a charge of 3 C, we use the formula W = V × Q. In this case, V = 12 V and Q = 3 C. Multiplying these values, we get W = 12 V × 3 C = 36 J. Therefore, the electric energy of the battery is 36 joules.

36 J

Answer 41. Provide the function of a live wire. [1]

The live wire carries current from the power source to the electrical appliance or device. It plays a crucial role in the proper operation of electrical circuits.

carries current to appliance

Answer 42. A 100 Ω resistor and a 150 Ω resistor connect in series to a 5 V battery. Calculate the total energy dissipated over 10 seconds in both resistors. [3]

To calculate the energy dissipated over 10 seconds in both the 100 Ω and 150 Ω resistors connected in series to a 5 V battery, we can use the formulas P = V²/R and E = Pt. First, we find the total resistance (R) in the circuit: R = 100 Ω + 150 Ω = 250 Ω.

Now we can calculate the power dissipated in both resistors using P = V²/R:
P = V²/R = (5 V)² / 250 Ω = 0.1 W

Finally, we can find the energy dissipated in both resistors using E = Pt:
E = P × t = 0.01 W × 10 s = 1 J

[3 marks] 1 J
[2 marks only] 1 or 0.1
[1 mark] 250

Answer 43. Explain why the Earth's magnetic North pole is equivalent to the South Pole if the Earth was a bar magnet. [1]

On Earth, a compass faces towards the Earth's magnetic North pole. However, since the magnetic field always faces from North to South, we can imagine the Earth as a bar magnet whose South pole lies at the Earth's magnetic North pole.

compass pointing towards magnetic North pole

Answer 44. State the criterion to use F = BIl for finding the force on a current-carrying conductor in a magnetic field. [1]

The magnetic field must be perpendicular to the conductor.

magnetic field perpendicular to conductor

Answer 45. Name the part of alternator that connects the coil to the rest of the circuit. [1]

A coil of wire held by a slip ring is rotated inside a magnetic field. Carbon brushes are in contact with the slip ring, so that the induced current can flow through them into a circuit.

brushes

Answer 46. A transformer comprises 1250 turns in the primary coil and 8720 in the secondary coil. Given that the voltage in the primary coil is 250.0 V, calculate the voltage in the secondary coil. [2]

NpVs = NsVp
1250 × Vs = 8720 × 250.0 V
Vs = (8720 × 250 V) ÷ 1250 = 1744 V

[2 marks] 1744 V
[1 mark] 1744 or 1250 × Vs = 8720 × 250.0

Answer 47. Explain why Pluto is not a planet of the Solar system. [1]

Pluto is not a planet in the Solar System because it does not meet all the criteria for classification as a planet. While it orbits the Sun and has enough mass to be nearly spherical, it has not cleared its orbit of other debris.

not cleared orbit of debris

Answer 48. An astronaut on a spacewalk accidentally lets go of a tool in low Earth orbit. Describe the motion of the tool after being released. [2]

Once the astronaut releases the tool, it continues to move horizontally at the same velocity as the astronaut. Since the tool is still subject to Earth's gravity, it will maintain a similar orbit around the planet. The tool will continue to "fall" around Earth in a curved path, much like a satellite in low Earth orbit.

[1 mark] maintaining velocity
[1 mark] orbiting Earth

Answer 49. The James Webb Space Telescope has a high clarity of images. Explain why clear pictures are important for studying the early universe. [2]

Clear pictures are essential for studying the early universe because they offer greater detail and precision when observing distant celestial bodies and phenomena. The James Webb Space Telescope's high clarity of images allows astronomers to gather more accurate data on the early universe, including the formation of the first stars and galaxies. Additionally, clearer images improve our understanding of dark matter and dark energy, as well as other phenomena associated with the Big Bang theory. High-resolution images provide a deeper understanding of the universe's origins and evolution, enabling scientists to refine their ideas and make new discoveries.

[1 mark] spotting further objects
[1 mark] accurate data

Answer 50. Compare the size of an atom and its nucleus. [1]

According to the nuclear model an atom consists of a nucleus that is approximately 10,000 times smaller than the atom itself and shells of electrons surrounding the nucleus.

nucleus approximately 10,000 times smaller

Answer 51. Define radiation. [1]

Radiation is the emission of energy through particles or waves. Some radiation is produced by radioactive decay when larger nuclei split into smaller ones.

emission of energy through particles or waves

Answer 52. Scientists are designing a nuclear power generator for a Moon base. What could we say about the half-life of an isotope they should use for power generation? [1]

Scientists should use an isotope with a longer half-life for power generation on the Moon base. It would be more efficient and safer than isotopes with shorter half-lives.

longer half-life

Answer 53. Name two main types of nuclear reactions. [2]

Nuclear reactions involve changes in an atom's nucleus. These reactions include fission and fusion.

[1 mark] fission
[1 mark] fusion

Answer 54. Provide a definition for condensing. [1]

Condensing is a process during which a material changes state from gas to liquid.

change from gas to liquid

Answer 55. Find the mass of 62 dm³ of water if it has a density of 1.0 kg/dm³. [2]

If we need to find the mass, we can rearrange the density formula to get mass = density × volume. Here, the density of water in the question is 1.0 kg/dm³, and the volume is 62 dm³. So, the mass of the water is mass = 1.0 kg/dm³ × 62 dm³ = 62 kg. Hence, the mass of the 62 dm³ of water is 62 kg.

[2 marks] 62 kg
[1 mark] 62 or mass = density × volume

Answer 56. A gas cylinder contains helium at a pressure of 200 kPa and a volume of 3 m³. The volume changes to 1.5 m³ without any temperature change. Calculate the new pressure of the gas. [2]

If the volume decreases to 1.5 m³ and the temperature remains constant, Boyle's law applies: P₁ × V₁ = P₂ × V₂. Substituting in the values: 200 kPa × 3 m³ = P₂ × 1.5 m³. Solving for P₂, we calculate P₂ = (200 kPa × 3 m³) / 1.5 m³ = 400 kPa.

[2 marks] 400 kPa
[1 mark] 400 or 400000 or 200 kPa × 3 m³ = P₂ × 1.5 m³

Answer 57. 57600 J of energy are released when a 12 kg steel block cools down by 10 °C. Calculate the specific heat capacity of steel. [2]

Q = mcΔT
57600 = 12 × c × 10
c = 57600 ÷ (12 × 10) = 480 J/kg°C

[2 marks] 480 J/kg°C
[1 mark] 480 or 57600 = 12 × c × 10

Answer 58. Angela boils 0.250 kg of water. Given that the specific latent heat of vaporisation for water is 2260000 J/kg, calculate the energy required for the water to boil. [1]

Q = ml
Q = 0.250 × 2260000 = 5.65 × 10⁵ J

5.65 × 10⁵ J

Answer 59. Calculate the pressure at the bottom of a swimming pool of depth 1.8 m, given that the density of water is 1000 kg/m³. [1]

P = hρg
P = 1.8 m × 1000 kg/m³ × 9.8 N/kg = 18000 Pa (2 s. f.)

18000 Pa

Answer 60. Describe the relationship between atmospheric pressure and altitude. [1]

Atmospheric pressure is inversely proportional to altitude. As the height above a surface increases, the amount of air lying above that point decreases. Therefore, there are less air molecules available to collide with the surface. Further, the weight of the air above that point decreases. This means that the atmospheric pressure acting on that surface decreases, in comparison to when it was at a lower altitude.

inversely proportional

Answer 61. State the definition of a force. [1]

A force is a push or a pull that arises from the interaction of an object with another.

push or pull interaction

Answer 62. Ophelia cycles to school to reduce her carbon footprint. Calculate the total distance Ophelia covers with constant speed using the velocity-time graph for her motion. [2]

Ophelia travels at constant speed between t = 25 s and t = 85 s. The difference between these times is 85 − 25 = 60 s. The speed she is travelling at during this time is 6 m/s. Thus, the distance she travels during this time is 60 s × 6 m/s = 360 m.

[2 marks] 360 m
[1 mark] 360 or 60

Answer 63. Describe the journey based on the given distance-time graph. [3]

In the first 15 seconds, the object is moving at a constant speed; therefore, the gradient of the graph is positive and constant. In the next 5 seconds, the object is stationary. Therefore, the graph is flat. In the last 10 seconds, the object is accelerating, increasing the gradient.

[1 mark] It travels at a constant speed for 15 s from 0 to 7 m.
[1 mark] It is then stationary for 5 s.
[1 mark] It then accelerates for another 10 seconds, reaching 26 m.

Answer 64. The gradient of a velocity-time graph in the first 10 seconds is found to be 1.5 m/s². Given that the velocity at the end of the 10 seconds is 20 m/s, calculate the velocity at 4 seconds. [2]

Acceleration is the gradient of a velocity-time graph.
v = u + at
20 = u + 1.5 × 6
u = 20 − 9 = 11 m/s

[2 marks] 11 m/s
[1 mark] 11 or 20 = u + 1.5 × 6

Answer 65. Explain why crumple zones are installed in cars. [1]

Crumple zones are built at the front of the car so that it slowly crumples during a collision, thus extending the time taken for the collision to occur. The greater the time is taken for a collision to occur, the less force will be felt.

increased collision time

Answer 66. Lena kicks a 0.4 kg ball for 0.25 seconds to provide it a velocity of 5 m/s. Calculate the force that Lena exerted on the ball. [2]

change in momentum = 0.4 kg × 5 m/s = 2 kgm/s
force = change in momentum ÷ time
force = 2 kgm/s ÷ 0.25 s = 8 N

[2 marks] 8 N
[1 mark] 8 or 2

Answer 67. Define what the elastic limit of a material is. [1]

The elastic limit of a material is the point up until when all forces are removed, the material will return to its original shape.

material back to original shape when forces removed

Answer 68. Calculate the extension of a spring when a force of 7 N is applied to it, given that it has a spring constant of 14 N/m. [1]

F = ke
7 N = 14 N/m × e
e = 7 ÷ 14 = 0.5 m

0.5 m

Answer 69. State the principle of moments. [1]

The principle of moments states that when a system is in equilibrium, the total size of the clockwise moment equals the total size of the anti-clockwise moment.

equal sizes of total moments in both directions

Answer 70. A lift elevates passengers using a 1650 N force to a 120 m height. Calculate the work done by the lift. [1]

W = Fd
W = 1650 N × 120 m = 198000 J

198000 J

Answer 71. A jack-in-a-box spring is compressed by 5 cm when the box is closed. Given that the spring constant is 40 N/m, calculate the elastic potential energy stored in the spring when the box is closed. [1]

1 m = 100 cm
5 cm = 0.05 m

E = 0.5ke²
E = 0.5 × 40 × 0.5² = 5 J

5 J

Answer 72. Define kinetic energy. [1]

The kinetic energy of an object is the energy it possesses because of its speed.

energy due to speed

Answer 73. Peter kicks a football. Name the energy store its kinetic energy converts to after it stops moving. [1]

This kinetic energy will slowly be transferred into heat energy as work is done against the frictional forces on the ball from the ground.

heat or thermal energy

Answer 74. A mechanical lift uses 196 J to lift a 4 kg object. Assuming no frictional forces and a gravitational field strength of 9.8 N/kg, calculate the height through which the box is lifted. [2]

mgh = E
4 × h × 9.8 = 196
h = 196 ÷ (4 × 9.8)
h = 5 m

[2 marks] 5 m
[1 mark] 5 or 4 × h × 9.8 = 196

Answer 75. An electric motor lifts a 4.5 kg brick to a height of 12 m in 10 seconds. Calculate the motor's power, assuming that the gravitational field strength g = 10 N/kg. [2]

The brick gains gravitational potential energy.
E = mgh
E = 4.5 kg × 10 N/kg × 12 m
E = 540 J

P = E ÷ t
P = 540 J ÷ 10 s
P = 54 W

[2 marks] 54 W
[1 mark] 54 or 540

Answer 76. A hairdryer uses 15 J of electrical energy.and outputs 3 J of heat. Find its percentage efficiency. [1]

efficiency = useful energy ÷ total energy
efficiency = 3 J ÷ 15 J = 0.2 = 20%

20%

Answer 77. Discuss the environmental impact of fossil fuels. [2]

Fossil fuels contribute to global warming since they release carbon dioxide when they are burned, which is a greenhouse gas.

[1 mark] carbon dioxide or greenhouse gas
[1 mark] global warming

Answer 78. Manila has broken her wrist and needs a scan to diagnose it. Explain why X-rays can be used for this scan. [1]

The body does not fully absorb X-rays. Therefore, they can be used internally for imaging broken bones.

not fully absorbed

Answer 79. Given that 150 cycles of a wave pass through a point on the wave in 3 seconds, calculate the time period of that wave. [1]

Frequency is the number of waves through a point in a given second.
f = 150 ÷ 3 = 50 Hz
T = 1 ÷ f
T = 1 ÷ 50 = 0.02 s

0.02 s

Answer 80. State the human ear hearing range. [1]

The human ear can hear sound waves from 20 Hz to 20000 Hz.

20 Hz - 20000 Hz

Answer 81. A light wave travels through the glass and comes out into the air. Explain what happens to the wave. [3]

When the wave enters a less dense medium at an angle to the normal, its speed increases, and it bends away from the normal. Since air is less dense than glass, refraction occurs, and the ray bends away from the normal.

[1 mark] to lower density
[1 mark] speed increase
[1 mark] refraction
[1 mark] away from normal

Answer 82. How does the wavelength relate to the transmission and absorption of waves? [2]

Longer wavelengths are usually associated with reflection at a glass boundary. Shorter ones are usually associated with transmission.

[1 mark] longer wavelengths: reflection
[1 mark] shorter wavelengths: transmission

Answer 83. Calculate the magnification of a lens, given that the object has a height of 1.2 cm and the image has a height of 18 mm. [2]

1.2 cm = 12 mm
M = 18 mm ÷ 12 mm = 1.5

[2 marks] 1.5
[1 mark] 12

Answer 84. Which of the following colours of sunglasses would be most suitable for use in hot countries to minimize the amount of heat absorbed by the glasses?

black, green, white, red, blue [1]

Black bodies absorb all wavelengths of light, converting them into heat, making black objects excellent absorbers but also excellent radiators of heat. On the other hand, white objects reflect most of the wavelengths of light, absorbing much less heat compared to darker colours. Therefore, for sunglasses in hot countries, the goal is to minimize heat absorption. Based on this understanding, the most suitable colour of sunglasses would be white, as white sunglasses would absorb the least amount of heat, making them more comfortable to wear in hot conditions.

white

Answer 85. Find the charge transferred by a 0.45 A current in 160 seconds. [1]

Using the formula I = Q / t, we can find the charge transferred (Q) by rearranging the formula as Q = I × t. In this case, I = 0.45 A and t = 160 s. Q = 0.45 A × 160 s = 72 C. The charge transferred is 72 coulombs.

72 C

Answer 86. Anish sets up a uniform electric field between two parallel plates connected to a power source. Suggest a method to determine which plate has a positive charge. [2]

We could use a positively charged test object, such as a small charged plastic rod. If the test object is attracted to a plate, that plate has a negative charge since opposite charges attract. Conversely, if the test object repels, the plate has a positive charge since like charges repel.

[1 mark] use positively charged test object
[1 mark] attraction: negative plate
[1 mark] repulsion: positive plate

Answer 87. Design an experiment to investigate the current-voltage characteristics of a diode. [4]

To investigate the current-voltage characteristics of a diode, you can set up an experiment using the following equipment: a diode, a power supply, a voltmeter, an ammeter, and connecting wires. Connect the diode, ammeter, and voltmeter in a series circuit, with the voltmeter across the diode and the ammeter in series with the diode. As we increase the potential difference, we record the corresponding current and voltage readings at different intervals. Switch the diode's orientation in the circuit to test the reverse bias and repeat the process. Plot the voltage (x-axis) against the current (y-axis) to create a graph representing the diode's current-voltage characteristics.

[1 mark] diode, power supply, voltmeter, ammeter
[1 mark] series circuit
[1 mark] record readings
[1 mark] plot graph

Answer 88. A 2500 Ω lamp connects to an ammeter that reads 1.50 A. Find the voltage applied to the lamp. [1]

Using Ohm's law (V = I × R), we can find the voltage (V) applied to the lamp. In this case, I = 1.50 A and R = 2500 Ω. V = 1.5 A × 2500 Ω = 3750 V. The voltage applied to the lamp is 3750 volts.

3750 V

Answer 89. Define potential difference. [1]

Potential difference (V) measures the amount of energy transferred per unit of charge (coulomb, C) as it moves from one point to another in a circuit. It arises from separating positive and negative charges within a power source. It drives charged particles through a circuit, allowing energy to transfer to the circuit's components.

energy transfer per unit of charge

Answer 90. Provide an advantage and a disadvantage of using high voltage. [2]

High voltage has the advantage of minimising energy loss during long-distance transmission, ensuring efficient delivery of electricity. However, it can be dangerous for domestic use due to the risk of electrical accidents. Low voltage, on the other hand, is safer for household and commercial applications but may result in higher energy losses when used for long-distance transmission.

[1 mark] higher efficient
[1 mark] more dangerous

Answer 91. Peter set up a circuit with a 12 V power supply, and a resistor with a resistance of 4.0 Ω. Calculate the power dissipation in the resistor. [2]

We can use the formula P = VI. First, we need to find the current (I) in the circuit using Ohm's law (V = IR): I = V / R = 12 V / 4.0 Ω = 3.0 A. Now, we substitute the values into the power formula: P = (12 V) × (3.0 A) P = 36 W. The power dissipation in the resistor is 36 watts.

[2 marks] 36 W
[1 mark] 36 or 3.0 or 3 or P = VI

Answer 92. Describe an induced magnet. [1]

Induced magnets occur when magnetic materials are placed in a magnetic field. Induced magnets are not magnets when they are not in the magnetic field.

magnetic material in magnetic field

Answer 93. Paula places an 80 cm wire in a 1.25 T magnetic field. A current of magnitude 3 A flows through the wire. Given that the whole wire lies in the magnetic field, calculate the magnitude of the force the wire feels. [2]

1 m = 100 cm
80 cm = 80 ÷ 100 m
80 cm = 0.80 m

F = BIl
F = 1.25 T × 3 A × 0.8 m = 3 N

[2 marks] 3 N
[1 mark] 3 or 0.8 or 0.80

Answer 94. Lola is holding a bar magnet. Jack moves a coil of wire near the magnet. Explain what happens. [2]

The movement of the coil of wire into the magnetic field of the bar magnet induces a voltage and, thus, a current. The current induced opposes the direction of movement. Therefore, the coil of wire is repelled away from the magnet.

[1 mark] induced voltage/current
[1 mark] coil repelled from magnet

Answer 95. What type of transformer has fewer turns in its secondary coil? [1]

Transformers are made up of a primary coil and a secondary coil wrapped around an iron core. A step-down transformer has more turns in the primary coil than in the secondary coil.

step-down

Answer 96. Describe the Moon. [2]

Earth's Moon is an example of a moon of a planet. It is a natural satellite that orbits Earth and is the fifth-largest moon in the Solar System. The Moon has a solid, rocky surface with numerous craters and mountains, and it plays a crucial role in creating tides on Earth.

[1 mark] natural satellite
[1 mark] solid/rocky surface
[1 mark] craters/mountains

Answer 97. A satellite goes from a lower orbit to a higher orbit around Earth. Predict the change in the satellite's motion. [2]

As the satellite moves from a lower orbit to a higher orbit, the gravitational force acting on it decreases due to the increase in orbital radius. As a result, the satellite requires a slower velocity to maintain a stable orbit. Consequently, the satellite's motion will become slower in the higher orbit.

[1 mark] lower gravitational force
[1 mark] slower velocity

Answer 98. Define red-shift in the context of Big Bang theory. [2]

Red-shift refers to the stretching of light emitted by celestial bodies as they travel through the expanding universe. As objects move away due to the universe's expansion, the wavelength of the light they emit increases, making it appear redder. This observation of red-shifted light from distant stars and galaxies supports the notion that the universe has been expanding since its inception, which is a key aspect of the Big Bang theory.

[1 mark] stretching of light
[1 mark] evidence for expanding universe

Answer 99. Determine the relative atomic mass of the atom shown in the diagram correct to 2 significant figures. [1]

The number of electrons in an atom is the same as the atomic number of the element. Since the atom has 6 electrons, its atomic number is 6. The element is carbon and it has a relative atomic mass of 12 (2 sf).

12

Answer 100. Peter has an idea of using irradiation to disinfect plastic food packaging. Discuss the suitability of this approach. [2]

Irradiation can be an effective method to disinfect plastic food packaging. Irradiation involves exposing the packaging to radiation to kill pathogens. It does not make the packaging itself radioactive.

[1 mark] killing pathogens
[1 mark] (ideally) no contamination

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