In a magnetic field,
(A) a charged particle in motion can experience a force
(B) a charged particle at rest, experiences a force
(C) there is no change in the speed of the charged particle
(D) there is a change in the kinetic energy of the charged particle.
Choose the correct answer from the options given below:
Answer & explanation
Correct answer: option 2
The correct answer is Option (2) → (A) and (C) only
(A) A charged particle in motion can experience a force — ✔ True (Magnetic force $F = q(\vec{v} \times \vec{B})$, nonzero if velocity has a component perpendicular to $\vec{B}$.)
(B) A charged particle at rest experiences a force — ✖ False (At rest, $\vec{v}=0$ ⇒ $\vec{F}=0$)
(C) There is no change in the speed of the charged particle — ✔ True (Magnetic force acts perpendicular to velocity ⇒ no work done ⇒ speed constant)
(D) There is a change in the kinetic energy of the charged particle — ✖ False (No work done by magnetic force ⇒ kinetic energy constant)
Final Answer:
(A) and (C)