Moving Charges and Magnetism

Two circular coils P and Q of 100 turns each have same radius of cm. The currents in P and Q are 1 A and 2 A respectively. P and Q are placed with their planes mutually perpendicular with their centers coincide. The resultant magnetic field induction at the center of the coils is x mT, where x= . [Use 0=4 10-7 TmA-1]

Two insulated circular loops A and B of radius 'a' carrying a current of 'I' in the anti clockwise direction as shown in the figure. The magnitude of the magnetic induction at the centre will be : [figure]

1. 2 0 Ia
2. 0 I 2a
3. 0I2a
4. 2 0 Ia

The horizontal component of earth's magnetic field at a place is 3.5 10-5 T. A very long straight conductor carrying current of 2 A in the direction from South east to North West is placed. The force per unit length experienced by the conductor is 10-6 N/m.

A current of 5 A flows in a square loop of side 1 m placed in air. The magnetic field at the centre of the loop is X 2 10-7 T. The value of X is .

The deflection in moving coil galvanometer falls from 25 divisions to 5 divisions when a shunt of 24 is applied. The resistance of galvanometer coil will be :

1. 48
2. 100
3. 96
4. 12

A galvanometer having coil resistance 10 shows a full scale deflection for a current of 3 mA. For it to measure a current of 8 A, the value of the shunt should be:

1. 3.75 10-3
2. 3 10-3
3. 4.85 10-3
4. 2.75 10-3

Two particles X and Y having equal charges are being accelerated through the same potential difference. Thereafter they enter normally in a region of uniform magnetic field and describe circular paths of radii R1 and R2 respectively. The mass ratio of X and Y is :

1. ( R1R2 )
2. ( R2R1 )
3. ( R2R1 )2
4. ( R1R2 )2

A charge of 4.0 is moving with a velocity of 4.0 106 ms-1 along the positive y axis under a magnetic field B of strength (2 k) T. The force acting on the charge is x i N. The value of x is .

A proton moving with a constant velocity passes through a region of space without any change in its velocity. If E and B represent the electric and magnetic fields respectively, then the region of space may have : Choose the most appropriate answer from the options given below :

1. (A), (B) and (C) only
2. (A), (C) and (D) only
3. (A), (B) and (D) only
4. (B), (C) and (D) only

Two long, straight wires carry equal currents in opposite directions as shown in figure. The separation between the wires is 5.0 cm. The magnitude of the magnetic field at a point P midway between the wires is (Given : 0 = 4 10-7 T m A-1) [figure]