MOVING CHARGES AND MAGNETISM Set 5

1.

A charge +

is moving upwards vertically. It enters a magnetic field directed to north. The force on the charge will be towards

North South East West NULL NULL NULL

2.

A length of wire carries a steady current. It is bent first to form a circular coil of one turn. The same length is now bent more sharply to give a double loop of smaller radius. The magnetic field at the centre caused by the same current is

Double of its first value Quarter of its first value Four times of its first value Same as the first value NULL NULL NULL

3.

A particle of mass

and charge

moves with a constant velocity

along the positive

direction. It enters a region containing a uniform magnetic field

directed along the negative

direction, extending from

to

. The minimum value of

required so that the particle can just enter the region

is

NULL NULL NULL

4.

and

are parallel conductors of equal length carrying currents

and

respectively. Distance between

and

is

. Distance between

and

is also

.

is the force exerted by

on

and

is the force exerted by

on

. Choose the correct answer

NULL NULL NULL

5.

When a positively charged particle enters a uniform magnetic field with uniform velocity, its trajectory can be
(1) a straight line
(2) a circle
(3) a helix

(1) only (1) or (2) (1) or (3) Any one of (1), (2) and (3) NULL NULL NULL

6.

A current

flow in an infinitely long wire cross-section in the form of a semi-circular ring of radius R. The magnitude of the magnetic induction along its axis is