Physics – Class 12 Mock Test 4

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Question 1 of 10

1. In the Wheatstone bridge given below, what should be values of R₁ and R₂ so that the bridge is balanced?

R₁ = 29.4; R₂ = 2 ohms

R₁ = 6 ohms; R₂ = 3 ohms

R₁ = 6 ohms; R₂ = any finite value

R₁ = any finite value; R₂ = 3 ohms

Question 1 of 10

Question 2 of 10

2. A current of 3 A passes through an electric circuit for 5 minutes and does a work of 900J. What is the emf of the source?

10V

Question 2 of 10

Question 3 of 10

3. There are 2 long parallel conductors AB and CD. AB carries 4A current and CD carries 3A current. The magnetic field at the midpoint of these 2 conductors is B. If 4A current is switched off, then what is the magnetic field at the midpoint now?

\(\frac {B}{3}\)

\(\frac {2B}{3}\)

Question 3 of 10

Question 4 of 10

4. A long solenoid has 500 turns per cm and carries a current I. The magnetic field at its center is 7.54 × 10^-2 Wb m^-2. Another long solenoid has 300 turns per cm and it carries a current \(\frac {I}{3}\). What is the value of magnetic field at the center?

1.50 × 10^-5 Wb/m²

1.50 × 10^-2 Wb/m²

1.05 × 10^-3 Wb/m²

1.50 × 10^-3 Wb/m²

Question 4 of 10

Question 5 of 10

5. A solenoid has core of a material with relative permeability 200 and its windings carry a current of 2 A. The number of turns of the solenoid is 200 per meter. What is the magnetization of the material?

7 × 10⁴ A/m

9 × 10⁴ A/m

8 × 10⁴ A/m

6 × 10⁴ A/m

Question 5 of 10

Question 6 of 10

6. The angle at which a charged particle moves through a magnetic field with a velocity, having zero magnetic force is 180^o.

False

True

Question 6 of 10

Question 7 of 10

7. Magnetic field in toroid is stronger than that in solenoid.

False

True

Question 7 of 10

Question 8 of 10

8. Give the SI unit of the magnetic field.

Tesla

Ampere

Weber

Oersted

Question 8 of 10

Question 9 of 10

9. Which of the following is correct when one cell is wrongly connected in series circuit?

The total emf reduces by e

The total emf increases by 2e

The total emf decreases by 2e

The total emf increases by e

Question 9 of 10

Question 10 of 10

10. If an electron entering at a magnetic field of 2 × 10^-2 T has a velocity of 3 × 10⁷ ms^-1 and describes a circle of radius 8 × 10^-3 m, then find the value of \(\frac {e}{m}\) of the electron.

1.875 × 10¹¹ C/Kg

18 × 10¹¹ C/Kg

1.567 × 10¹¹ C/Kg

190 × 10¹¹ C/Kg

Question 10 of 10