NEET Physics Question - Magnetic Effects of Current

Assertion (A): A charged particle moving in a magnetic field in general, experiences a force but its kinetic energy remains constant.

Reason (R): Work done by magnetic force is always zero.

Both (A) & (R) are true and the (R) is the correct explanation of the (A)

Both (A) & (R) are true but the (R) is not the correct explanation of the (A)

(A) is true but (R) is false

Both (A) and (R) are false

Solution:

Magnetic force \( \vec{F} = q(\vec{v} \times \vec{B}) \) is always perpendicular to velocity \( \vec{v} \). Thus, work done \( W = \vec{F} \cdot d\vec{r} = 0 \). By the Work-Energy Theorem, if work done is zero, the kinetic energy remains constant. Both assertion (A) and reason (R) are true, and (R) correctly explains (A).

Rankers Physics

Assertion and Reason: Magnetic Force and Kinetic Energy

Solution:

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