Physics – Class 12 Mock Test 5

1. When 0.010A current flows through a moving coil galvanometer, it gives full deflection. Then, it is converted into a voltmeter which gives a reading of 10 V using an external resistance of 950 Ω. What is the resistance of the galvanometer (G)?

2. When is the magnetic flux said to be positive?

3. Calculate the torque on a 500 turn rectangular coil of length 20 cm and breadth 10 cm, carrying a current of 30 A, when placed making an angle of 60^o with a magnetic field of 0.5 T?

4. Give the SI unit of magnetic dipole moment.

5. A bar magnet of the magnetic moment 5 Am² has poles 20 cm apart. Calculate the pole strength.

6. A magnetized needle of the magnetic moment 20 JT^-1 is placed at 60^o with the direction of the uniform magnetic field of magnitude 9 T. What is the torque acting on the needle?

7. Identify the expression for Curie’s constant from the following.

8. ‘X’ states that the direction of induced current in a circuit is such that it opposes the cause or the change which produces it. Identify X.

9. At a given place on the Earth’s surface, the horizontal component of Earth’s magnetic field is 9 × 10^-5 T and the resultant magnetic field is 180 × 10^-6. Calculate the angle of dip at this place.

10. Calculate the magnetic flux when the magnetic field is perpendicular to the surface area.