Question

Given below are two statements, one is labelled as Assertion A and the other is labelled as Reason R
Assertion (A) : The centre of mass of an electron and proton, when released moves faster towards proton.

Reason (R) : This is because proton is heavier.

In the light of the above statements, choose the correct answer from the options given below

• A. If both assertion and reason are true and reason is the correct explanation of assertion
• B. If both assertion and reason are true but reason is not the correct explanation of assertion
• C. If assertion is true but reason is false
• D. If both assertion and reason are false

Answer 1

Answer: (D)

If both assertion and reason are false

Answer 2

As $qE=\frac{mv^{2}}{r}$, $r=\frac{mv^{2}}{qE}$ $=\frac{2K}{qE}$ (where $K=\frac{1}{2}mv^{2}$ i.e, $r \propto\frac{1}{q}$ Since electron and proton have equal charge, r is the same for both of them Here, $r$ depends on $K$ (which is given to be the same for both the particles) and as such not on their masses