# Electric Charge - Chapter No 19

Right Answers have been shown below in red color.

1. A coulomb is the same as:

A. an ampere/second
B. half an ampere·second2
C. an ampere/meter2
D. an ampere·second
E. a newton·meter2

2. A kiloampere·hour is a unit of:

A. current
B. charge per time
C. power
D. charge
E. energy

3. The magnitude of the charge on an electron is approximate:

A. 1023 C
B. 10-23 C
C. 1019 C
D. 10-19 C
E. 109 C

4. The total negative charge on the electrons in 1 mol of helium (atomic number 2, molar mass 4) is:

A. 4.8 × 104 C
B. 9.6 × 104 C
C. 1.9 × 105 C
D. 3.8 × 105 C
E. 7.7 × 105 C

6. A wire carries a steady current of 2 A. The charge that passes a cross-section in 2 s is:

A. 3.2 × 10−19 C
B. 6.4 × 10−19 C
C. 1 C
D. 2 C
E. 4 C

7. A wire contains a steady current of 2 A. The number of electrons that pass a cross-section in 2 s is:

A. 2
B. 4
C. 6.3 × 1018
D. 1.3 × 1019
E. 2.5 × 1019

8. The charge on a glass rod that has been rubbed with silk is called positive:

A. by arbitrary convention
B. so that the proton charge will be positive
C. to conform to the conventions adopted for G and m in Newton’s law of gravitation
D. because like charges repel
E. because glass is an insulator

9. To make an uncharged object have a negative charge we must:

B. remove some atoms
D. remove some electrons
E. write down a negative sign

10. To make an uncharged object have a positive charge:

A. remove some neutrons
D. remove some electrons
E. heatit to cause a change of phase

11. When a hard rubber rod is given a negative charge by rubbing it with wool:

A. positive charges are transferred from rod to wool
B. negative charges are transferred from rod to wool
C. positive charges are transferred from wool to rod
D. negative charges are transferred from wool to rod
E. negative charges are created and stored on the rod

12. An electrical insulator is a material:

A. containing no electrons
B. through which electrons do not flow easily
C. that has more electrons than protons on its surface
D. cannot be a pure chemical element
E. must be a crystal

13. A conductor is distinguished from an insulator with the same number of atoms by the number of:

A. nearly free atoms
B. electrons
C. nearly free electrons
D. protons
E. molecules

14. The diagram shows two pairs of heavily charged plastic cubes. Cubes 1 and 2 attract each other and cubes 1 and 3 repel each other.

Which of the following illustrates the forces of cube 2 on cube 3 and cube 3 on cube 2?

15. The diagram shows a pair of heavily charged plastic cubes that attract each other.

Cube 3 is a conductor and is uncharged. Which of the following illustrates the forces between cubes 1 and 3 and between cubes 2 and 3?

16. A neutral metal ball is suspended by a string. A positively charged insulating rod is placed near the ball, which is observed to be attracted to the rod. This is because:

A. the ball becomes positively charged by induction
B. the ball becomes negatively charged by induction
C. the number of electrons in the ball is more than the number in the rod
D. the string is not a perfect insulator
E. there is a rearrangement of the electrons in the ball

17. A positively charged insulating rod is brought close to an object that is suspended by a string. If the object is attracted toward the rod we can conclude:

A. the object is positively charged
B. the object is negatively charged
C. the object is an insulator
D. the object is a conductor
E. none of the above

18. A positively charged insulating rod is brought close to an object that is suspended by a string. If the object is repelled away from the rod we can conclude:

A. the object is positively charged
B. the object is negatively charged
C. the object is an insulator
D. the object is a conductor
E. none of the above

19. Two uncharged metal spheres, L and M, are in contact. A negatively charged rod is brought close to L, but not touching it, as shown. The two spheres are slightly separated and the rod is then withdrawn. As a result:

A. both spheres are neutral
B. both spheres are positive
C. both spheres are negative
D. L is negative and M is positive
E. L is positive and M is negative

20. A positively charged metal sphere A is brought into contact with an uncharged metal sphere B. As a result:

A. both spheres are positively charged
B. A is positively charged and B is neutral
C. A is positively charged and B is negatively charged
D. A is neutral and B is positively charged
E. A is neutral and B is negatively charged