Practice MCQ Questions and answers on Physics-GK

1

Kirchoff's Voltage Law is known as

A) Conservation of Charge B) Conservation Energy C) Both D) None of these

Discuss

Answer & Solution

Answer: Option B

Solution:

Kirchhoff's Voltage Law (KVL) is Kirchhoff's second law that deals with the conservation of energy around a closed circuit path.

2

Super conductors are substances that

A) Offer minimum resistance to flow of electric current B) Conduct electricity at low temperature C) Conduct electricity at high temperature D) Offer high resistance to the flow of electric current

Discuss

Answer & Solution

Answer: Option A

Solution:

Superconductors are substances which display zero electrical resistance when a current is supplied, and are able to propagate such a current in a circuit indefinitely.

3

A galvanometer can be converted to a voltmeter by connecting

A) A high resistance in parallel B) A high resistance in series C) A low resistance in series D) A low resistance in parallel

Discuss

Answer & Solution

Answer: Option B

Solution:

A galvanometer is converted into a voltmeter by connecting with high resistance.

4

Certain substances loose their electrical resistance completely at super low temperature. Such substances are called.

A) Superconductors B) Semi conductors C) Dielectrics D) Perfect conductors

Discuss

Answer & Solution

Answer: Option A

Solution:

The substances which lose their resistance completely at very low temperature are called Superconductors.

5

The potential difference between the terminals of an electric heater is 60 V when it draws a current of 4 A from the source. What current will the heater draw if the potential difference is increased to 127.5 V ?

A) 8.5 A B) 24 A C) 10 A D) 12 A

Discuss

Answer & Solution

Answer: Option A

Solution:

V = 60V and I = 4A
R = V/I
= 60/4
=15Ω
When potential difference is increased to 127.5 V
I = V/R
= 127.5/15
= 8.5 A
The current through the heater becomes 8.5 A.

6

Which of the following experiments analyzed the Fraunhofer lines of the solar spectrum?

A) Barkla's experiment on scattering of X-rays B) Lamb-Rutherford experiment C) Geiger and Marsdens experiment on scattering of alpha particles D) Bunsen and Kirchhoff's experiment

Discuss

Answer & Solution

Answer: Option D

Solution:

Bunsen and Kirchhoff's experiment analyzed the Fraunhofer lines of the solar spectrum.

7

Erg cross Sec is the unit of

A) Angular momentum B) Linear Momentum C) Planck's constant D) Energy

Discuss

Answer & Solution

Answer: Option C

Solution:

Erg * Sec is the unit of Planck's Constant.

8

A dynamometer wattmeter can be used for

A) Only Direct Current B) Only Active Current C) Both A & B D) None of the above

Discuss

Answer & Solution

Answer: Option C

Solution:

Dynamometer type wattmeter is used for the measurement of A.C. as well as D.C. power. It consists of a fixed coil forming the current coil whereas the moving coil forms the potential coil.

9

Kirchhoff's laws are applicable to

A) D.C. circuits only B) A.C. circuits only C) D.C. and A.C. circuits both D) None of the above

Discuss

Answer & Solution

Answer: Option C

Solution:

Kirchhoff's laws are applicable to both D.C. and A.C. circuits.

10

The device which converts AC to DC is

A) Oscillator B) Amplifier C) Rectifier D) None of these

Discuss

Answer & Solution

Answer: Option C

Solution:

A rectifier is an electrical device that converts alternating current (AC), which periodically reverses direction, to direct current (DC), which flows in only one direction. The process is known as rectification, since it "straightens' the direction of current.