Question:
The fact that the magnetic field generates a force perpendicular to the instantaneous velocity of the particle has implications for the work that the field does on the particle. As a consequence, if only the magnetic field acts on the particle, its kinetic energy will ____________.
__ increase over time
__ decrease over time
__ remain constant
__ oscillate
Answer:
Remain constant
Explanation:
By the formula of work done,
Change in kinetic energy = Work done
final kinetic energy - initial kinetic energy = Force × distance × cosθ
final kinetic energy - initial kinetic energy = Force × velocity × time × cosθ
∵ θ = 90 degree
cos 90 = 0
final kinetic energy - initial kinetic energy = 0
final kinetic energy = initial kinetic energy
