# Further electricity for OCR GCSE Physics

1. Static electricity
2. Electric fields

If an atom loses an electron, it will become positively charged, since there will be more protons than electrons. If an atom gains an electron, it will become negatively charged, since there will be more electrons than protos. These charged particles are called ions and they will exert non-contact electrostatic forces of static electricity on other charged objects. Oppositely charged objects will attract each other, whereas like charges will repel each other. When insulating materials are rubbed together, they may become electrically charged as electrons are rubbed off from one material to another. Since insulators will prevent electrons from moving between the materials, the charge formed is static.

Charged objects have an electric field around them. Electric fields are regions in which charges experience an electrostatic force. In electric fields, arrows will point from positive to negative, showing the direction in which a positive charge will experience a force. Electric fields with arrows that are closer together will be stronger, and thus the electrostatic forces they will exert will be stronger. Around a point charge, the electric field will be a radial field. The field between two parallel plates is called a uniform field. A strong enough electric field may force charges to move through insulators, which will result in sparking.

# 1

Explain why sometimes touching someone may cause a small shock to occur between the two people.

A strong enough electric field may force charges to move through insulators. One of the people touching each other may be electrically charged, therefore causing sparking and a small shock to be felt.

# 2

An acetate rod is rubbed with a cloth. Electrons are rubbed off from the rod onto the cloth. Describe the charge of each object.

Since the acetate rod loses electrons, it becomes positively charged, whereas since the cloth gains electrons, it becomes negatively charged.

# 3

A polythene rod is rubbed with a cloth and electrons are rubbed off from the cloth to the rod. Explain the charge of each object.

Since the polythene rod gains electrons, it becomes negatively charged, whereas since the cloth loses electrons, it becomes positively charged.

# 4

Draw the electric field around a proton.

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# 5

State what electrically charged atoms are called.

Electrically charged atoms are called ions.

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