Assertion: There is no change in the energy of a charged particle moving in a magnetic field although a magnetic force is acting on it.
Reason: Work done by a centripetal force is always zero.
(a) Both A and R are true and R is the correct explanation of A.
(b) Both A and R are true but R is not the correct explanation of A.
(c) A is true but R is false.
(d) A is false but R is true.
Give explanation for your answer.
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| CBSE | Class X
Answers
Answer:
Hey!!
The answer to your question is:
(a) Both Assertion and Reason are correct and The reason is the correct explanation of the Assertion.
Explanation:
Look, the Assertion and Reason are absolutely correct. Now, we need to find if the reason is the correct explanation of Assertion.
When an electron enters a magnetic field, it experiences a magnetic force due to the opposition in magnetic fields.(already existing and that induced by charged particle)
Thus, the electron will be deflected.
Here, the electron is rotated in a circular motion untill its in the field due to the force.
We know, that work done by a body when experiences a centripetal force is zero.
work done by a body when experiences a centripetal force is zero.
and, hence the energy is conserved.
I hope it helps!! ✌
(a) Both A and R are true and R is the correct explanation of A.
Assertion :
We know that, the magnitude of deflection increases with the increase in the strength of current and vice versa. The magnetic force always remains perpendicular to the direction of of motion of the charged particle. Hence, even if a magnetic force acts on a charged particle moving in a magnetic field, there is no change in the energy.
Reason :
From the assertion, it is known that even if the direction changes, there is no change in the speed of the particle. Magnetic force can change the velocity but not the speed, hence the kinetic motion of the particle remains constant. Hence, we can say that work done by centripetal force is always zero.