Ch:17 Static electricity

A polythene rod is charged negatively by rubbing it with a cloth. Which statement explains why the rod has become charged?

• A The rod has gained electrons.

• B The rod has gained protons.

• C The rod has lost electrons.

• D The rod has lost protons.

Which statement about charging an insulator is correct?

• A It can be given an electrostatic charge by placing it in a magnetic field.

• B It can be given an electrostatic charge by connecting it to a battery.

• C It can be given an electrostatic charge by friction.

• D It cannot be given an electrostatic charge.

Each of the four diagrams M, N, O and P shows a separate pair of insulating rods. Each rod is charged as shown.In which two arrangements do the pairs of rods experience a force of repulsion?

• A M and N

• B O and P

• C M and P

• D N and O

The diagram shows a positively charged conducting sphere and a wire connected to earth. What happens when the wire is touched onto the sphere?

• A Electrons flow from earth to the sphere.

• B Electrons flow from the sphere to earth.

• C Positive charges flow from earth to the sphere.

• D Positive charges flow from the sphere to earth.

A negatively charged plastic rod is brought near to an uncharged metal sphere and held there. What happens when the metal sphere is earthed?

• A Electrons flow from the metal sphere to earth.

• B Electrons flow from earth to the metal sphere.

• C Positive charge flows from the metal sphere to earth.

• D Positive charge flows from earth to the metal sphere.

A cloth is used to rub an uncharged plastic rod. Both the rod and the cloth become charged. Why does the plastic rod become negatively charged and the cloth become positively charged?

• A The rod gains electrons and the cloth gains positive charges.

• B The rod gains electrons and the cloth loses electrons.

• C The rod loses electrons and the cloth gains electrons.

• D The rod loses electrons and the cloth loses positive charges.

• A

• B

• C

• D

• A

• B

• C

• D

A plastic rod is rubbed with a cloth. The rod becomes positively charged. What happens to the plastic rod and what is the charge on the cloth?

• A

• B

• C

• D

• A

• B

• C

• D