Charging by Friction

Q.

If an object made of substance A is rubbed with an object made of substance B, then A becomes positively charged and B becomes negatively charged. If, however, an object made of substance A is rubbed against an object made of substance C, then A become negatively charged. What will happen if an object made of substance B is rubbed against an object made of substance C?

1. B becomes positively charged and C becomes positively charged.

2. B becomes positively charged and C becomes negatively charged.

3. B becomes negatively charged and C becomes positively charged.

4. B becomes negatively charged and C becomes negatively charged.

Q.

If two bodies were rubbed against each other and one aquired a -5mC charge, what will be the charge on the other body?

1. -5mC

2. +5mC

3. -3mC

4. +3mC

Q. When a glass rod is rubbed with silk, it

1. Gives electrons to silk
2. Gains protons from silk
3. Gains electrons from silk
4. Gives protons to silk

Q. If two neutral bodies were rubbed against each other and one aquired a -5 mC charge, then the charge on the other body is .

1. +3 mC
2. +5 mC
3. -3 mC
4. -5 mC

Q. When a glass rod is rubbed with silk, it

1. Gains protons from silk
2. Gains electrons from silk
3. Gives electrons to silk
4. Gives protons to silk

Q. During "charging by friction", the masses of the bodies rubbing against each other remain the same.

1. False
2. True

Q. When a glass rod is rubbed with a silk cloth, charges appear on both. A similar phenomenon is observed with many other pairs ofbodies. Explain how this observation is consistent with the law ofconservation of charge.

Q. A polythene piece rubbed with wool is found to have a negativecharge of 3 × 10–7 C. (a) Estimate the number of electrons transferred (from which towhich?) (b) Is there a transfer of mass from wool to polythene?

Q. What causes electrification of two bodies when they are rubbed together ?

1. Transfer of atoms from one body to the other body.
2. Transfer of electricity from one body to the other body.
3. Transfer of electrons from one body to the other body.
4. Transfer of heat from one body to the other body.

Q. When a glass rod is rubbed with silk, it is said to be positively charged. Which of the following statement is true?

1. Electrons move from silk to glass
2. Electrons move from glass to silk
3. Protons move from silk to glass
4. Protons move from glass to silk