Electricity

Part: 1

1. What is the SI unit of current?
a) Coulomb (C)
b) Ampere (A)
c) Farad (F)
d) Newton (N)

2. The presence of free ________ in a substance makes it a conductor of electricity.
a. Positrons
b. Protons
c. Electrons
d. Neutrons
e. None of the above
Answer: c. Electrons

3. What is the number of electrons that constitutes a current of one Ampere?
a) 2.25 × 10¹⁸
b) 2.25 × 10^-18
c) 6.25 × 10¹⁸
d) 6.25 × 10^-18

4. Which of these is a correct definition of conventional current?
a) Current that flows from lower potential to higher potential
b) The current which remains static
c) Current constituted by the flow of ions
d) Current that flows from higher potential to lower potential

5. Which type of current is flowing through a circuit?
a) Static current
b) Conventional current
c) Electronic current
d) Potential current

6. In electrolytes and ionic crystals, the current carriers are free electrons.
a) True
b) False
Answer: b
Explanation: In electrolytes and ionic crystals, the current carriers are positive and negative ions. Whereas in most of the substances like metals, the carriers of electric current are electrons.

7. Alternating current is not used in:
a. Transformers
b. Electric heaters
c. Electric geysers
d. Electro plating
e. dynamo
Answer: d. Electro plating

8. Which type of physical quantity is electric current?
a) Scalar quantity
b) Vector quantity
c) Bipolar quantity
d) Thermodynamic quantity

9. Which of these is a correct definition of electronic current?
a) Current that flows from lower potential to higher potential
b) The current which remains static
c) Current constituted by the flow of ions
d) Current that flows from higher potential to lower potential

10. What is the study of electric charges in motion called?
a) Charge mobility
b) Electronic mobility
c) Static electricity
d) Current electricity
View Answer

Part: 2

Q1. The poorest conductor of heat among the following is

a. copper

b. lead

c. mercury

d. zinc

e. None of the above/More than one of the above

Answer: b: lead

Q2. The frequency of the direct current is

a. Zero

b. 50 Hz

c. 60 Hz

d. 100 Hz

e. None of the above/More than one of the above

Answer: a: Zero

Q3. Which of the following is NOT based on the heating effect of current?

a. Electric heater

b. Electric bulb (with filament)

c. Electric iron

d. Microwave

Answer: d: Microwave

Q4. A device used for converting AC into DC is called

a. Transformer

b. Rectifier

c. Induction coil

d. Dynamo

Answer: b. Rectifier

Q5. Which one of the following is not a conductor of electricity?

a. Vinegar

b. Lime juice

c. Salt water

d. Distilled water

Answer: d. Distilled water

Q6. To which of the following fields of science do “Kirchhoff’s Rules” belong?

a. Atomic structure

b. Electrical circuits

c. Organic chemistry

d. Optics

Answer: b. Electrical circuits

Q7. Electric wires are generally coated with:

a. Polypropylene

b. Polyvinyl chloride

c. Polyurethane

d. Polyethylene

Answer: b. Polyvinyl chloride

Q8. Superconductors are substances that

a. conduct electricity at lower temperatures.

b. offer high resistance to the flow of current.

c. offer no resistance to the flow of current.

d. conduct electricity at high temperatures.

Answer: c. offer no resistance to the flow of current.