The core of a transformer is laminated to reduce the effect of

Assertion (A) : A negative charge in an electric field moves along the direction of the electric field.

Reason (R) : On a negative charge a force acts in the direction of the electric field.

Assertion (A) : The poles of a bar magnet cannot be separated.

Reason (R) : Magnetic monopoles do not exist.

Assertion (A) : When radius of a current carrying loop is doubled, its magnetic moment becomes four times.

Reason (R) : The magnetic moment of a current carrying loop is directly proportional to the area of the loop.