For of particles under central forcer field, the total angular momentum is conserved.
The torque acting on such a system is zero.

Options

A. If both assertion and reason are true and reason is the true explanation of assertion.
B. If both assertion and reason are reason are true but reason is not the correct explanation of assertion.
C. If assertion is true but reason is false
D. If both assertion and reason are false.

Answer

A

Explanation

(a) When a body rotates about an axis under the action of an external torque `t`, then the rate of change of angular momentum of the body is equal to the torque, that is
`(d J)/(dt) = tau`
If external torque is zero `(tau = 0)`, then
`(d J)/(dt) = 0`
`rArr d J = 0`
`rArr J = contant`
Thus, angular momentum remains conserved.