 # Radiation for OCR GCSE Physics 2. Experimental identification
3. Nuclear equations

There are three types of radiation: alpha, beta and gamma. An alpha particle is a helium nucleus and is made up of two protons, two neutrons and no electrons. A beta particle is an electron. Gamma radiation is a high energy electromagnetic wave with really short wavelength and high frequency. Gamma rays are released when an atom is in a high energy state after emitting an alpha or beta particle to return to a stable state.  Nuclear equations describe what happens when a nucleus changes into another element by alpha or beta decay. In alpha decay, 2 protons and 2 neutrons are released from the nucleus to release an alpha particle, thus the atomic number decreases by 2 and the mass number decreases by 4. In beta decay, a neutron changes into a proton and releases an electron, thus the mass number stays the same and the atomic number increases by 1. Background radiation is radiation that exists around us at all times. This can be from both naturally occuring or artificial sources. Some natural sources of background radiation are radon gas from radioactive emitting rocks and soil in the ground, cosmic rays that reach the Earth from space and living things, as plants absorb radioactive materials from the soil they grow in and pass them up through the food chain. Some artificial sources of background radiation are medical procedures and nuclear power and weapons. When conducting experiments involving radiation, the background radiation must first be calculated and deducted from all results so as not to interfere with them. # 1

A potassium nucleus ⁴²₁₉K emits a beta particle. Write the nuclear equation for this beta decay.

⁴²₁₉K → ⁴²₂₀Ca + ⁰₋₁β # 2

Write the nuclear equation for a lithium nucleus ⁷₃Li emitting an alpha particle.

⁷₃Li → ³₁H + ⁴₂a # 3

Fill in the gaps of the given nuclear equation.

²¹⁰₈₄Po → ⁴ₐHe + ᵇₑPb

a = 2, b = 206, e = 82. # 4

What are the three types of radiation?

Radiation can be emitted as an alpha particle, a beta particle or a gamma particle. # 5

Explain what happens to a nucleus that undergoes alpha decay.

When a nucleus undergoes alpha decay, it loses two protons and two neutrons, which are emitted as an alpha particle. The mass number of the nucleus decreases by 4 and the atomic number decreases by 2. End of page