Question 136 of 276
Given below are two statements :
Statement : The electric force changes the speed of the charged particle and hence changes its kinetic energy; whereas the magnetic force does not change the kinetic energy of the charged particle.
Statement : The electric force accelerates the positively charged particle perpendicular to the direction of electric field. The magnetic force accelerates the moving charged particle along the direction of magnetic field.
In the light of the above statements, choose the most appropriate answer from the options given below :
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Answer: (C) Statement is correct but Statement is incorrect.
When a charged particle moves in an electric field, the field applies an electric force along the field, so work done by electric field is non-zero resulting in accelerated motion, thus kinetic energy changes.
When a particle moves in a uniform magnetic field, the force due to magnetic field on it is perpendicular to its velocity, as force .
Since the magnetic field is constant, so force is constant. So, its direction of velocity constantly changes, but magnitude of velocity remains same. Hence, kinetic energy also does not change.
Electric field accelerates the particle in the direction of field and magnetic field accelerates the particle perpendicular to the field .
When a particle moves in a uniform magnetic field, the force due to magnetic field on it is perpendicular to its velocity, as force .
Since the magnetic field is constant, so force is constant. So, its direction of velocity constantly changes, but magnitude of velocity remains same. Hence, kinetic energy also does not change.
Electric field accelerates the particle in the direction of field and magnetic field accelerates the particle perpendicular to the field .
