Question

Assertion : On changing the direction of flow of current through a straight conductor, the direction of a magnetic field around the conductor is reversed. Reason: The direction of magnetic field around a conductor can be given in accordance with left hand thumb rule. (a) Both assertion (A) and reason (R) are true and reason (R) is the correct explanation of assertion (A). (b) Both assertion (A) and reason (R) are true but reason (R) is not the correct explanation of assertion (A). (c) Assertion (A) is true but reason (R) is false. (d) Assertion (A) is false but reason (R) is true

Answer 1

Answer:c

Explanation:

1)A TRUE;MAGNETIC FIELD IS PROPORTIONAL TO CURRENT

REASON:FALSE;DIRECTION IS DETERMINED BY RIGHT HAND THUMB RULE

Answer 2

The right option is b):

Explanation:

(b) Both assertion (A) and Reason (R) are true but reason (R) is not the correct explanation of assertion (A).

• i) When the current in a straight current conductor is increased, the strength of the magnetic field around the conductor increases, and vice versa.

• (ii)If the current through a straight current-carrying conductor is reversed, the direction of the magnetic field around that conductor is reversed.

     RIGHT HAND THUMB RULE:

• A current in a straight wire produces a magnetic field that spirals around the wire in a ring.
• Curl your fingers and point your right thumb towards the direction of the current in the wire to find it.
• The magnetic field around the wire will cause your fingers to curl in the same direction.