MCQ Drift of Electrons and Resistivity, Class 12 Physics

1. There will be total 20 MCQ in this test.
2. Please keep a pen and paper ready for rough work but keep your books away.
3. The test will consist of only objective type multiple choice questions requiring students to mouse-click their correct choice of the options against the related question number.
4. No negative marking for incorrect choice.
5. Please click on “Finish the Test” when you want to exit.
6. All the best – Happy Studying

1. If the resistivity of an alloy is ρ' and that of metal is ρ, then

ρ'>ρ

ρ'=ρ

ρ'<ρ

No relation between ρ' and ρ

Question 1 of 20

2. For semiconductors, the major factor affecting the value of resistivity when temperature changes is

n: the number of free electrons per unit volume

e: the charge of an electron

m: the mass of an electron

τ:average time between collisions

Question 2 of 20

3. When a conductor is placed in an external electric field, the acceleration of its electrons will be

A

B

C

D

Question 3 of 20

4. Resistors can be wire bound or carbon resistors. Wire bound resistors are generally made of

Aluminium

Carbon

Copper

Manganin

Question 4 of 20

5. The dimension of the temperature coefficient of resistivity is

(temperature.ohm)^-1

same as temperature.ohm

same as (temperature)^-1

same as (temperature)²

Question 5 of 20

6. The winding of a motor has a resistance of 80 ohms at 15°C. Find its resistance at 50° C. the temperature co-efficient of resistance is 0.004/°C

60.57Ω

75.47Ω

90.56Ω

80.0Ω

Question 6 of 20

7. On heating a conductor its resistance

depends on type of metal

remains constant

increases

decreases

Question 7 of 20

8. Specific resistance of a conductor increases with

Increase in cross-section and decrease in length

Increase in cross-section

Decrease in cross-section

Increase in temperature

Question 8 of 20

9. A steady current flows in a metallic conductor of non-uniform cross-section. The quantity/quantities constant along the length of the conductor is/are

Current and drift speed

Current, electric field and drift velocity

Speed only

Current only.

Question 9 of 20

10. A current of 2 ampere is passing through a metallic wire of cross-sectional area 2 x 10^-6 m². If the density of the charge carriers in the wire is 5 x 10²⁶ m^-3, then the drift velocity of the electrons will be

1.15 x 10^-6 m/s

1.5 x 10^-5 m/s

1.25 x 10^-2 m/s

1.05 x 10^-3 m/s

Question 10 of 20

11. The standard resistance coil are made of "manganin" because

Temperature coefficient of resistance remain constant

Temperature coefficient of resistance is very low

Temperature coefficient of resistance is very high

Temperature coefficient of resistance is moderate

Question 11 of 20

12. If the potential difference V applied on a conductor is doubled, the drift velocity of electrons will become

A

B

C

D

Question 12 of 20

13. When a conductor is placed in an electric field, the force experienced by its electrons will be

A

B

C

D

Question 13 of 20

14. Resistance of a conductor depends on

length

length, area of cross-section, nature of material, temperature of conductor

length and area of cross-section

length, area of cross-section, nature of material

Question 14 of 20

15. A carbon resistor is marked in green, red, and orange bands. The approximate resistance of the resistor is

A

B

C

D

Question 15 of 20

16. Two special characteristics of the element of an electric heater:

low resistivity and high melting point

low resistivity and low melting point

high resistivity and low melting point

high resistivity and high melting point

Question 16 of 20

17. The type of materials whose resistivity is affected on adding the impurity is known as

Semiconductor

Insulator

Iron alloys

Conductor

Question 17 of 20

18. The average time that elapses between two successive collisions of an electron is called

Drift velocity

Free time

Relaxation time

Collision time

Question 18 of 20

19. Mobility of charge carriers in a conductor is given by

( charge of an electron).drift velocity/ electric field

drift velocity/ electric field

mass of an electron.(drift velocity/ electric field)

(drift velocity)(electric field)

Question 19 of 20

20. Manganin and constantan have a low temperature coefficient of resistivity which means that

their resistance values change very little with temperature

their resistance values only change at low temperatures

their resistance values change greatly with temperature

their resistance values do not change with temperature

Question 20 of 20

 Loading...