NEET2026PhysicsChapterActual
Given below are two statements: one is labelled as Assertion (A) and the other is labelled as Reason (R). Assertion (A): When a radioactive nucleus moving with a constant velocity in free space decays into two fragments, both the fragments must necessarily move along the same straight line path as the original nucleus. Reason (R): Radioactive decay is a result of internal forces, and internal forces cannot change the
Options
- ABoth (A) and (R) are correct and (R) is the correct explanation of (A)
- BBoth (A) and (R) are correct but (R) is not the correct explanation of (A)
- C(A) is correct but (R) is not correct
- D(A) is not correct but (R) is correct
Correct answer
D. (A) is not correct but (R) is correct
Step-by-step solution
Assertion (A) is incorrect because when a radioactive nucleus decays, the fragments can be emitted in any direction in the center of mass frame. In the laboratory frame, their velocities will have components perpendicular to the original direction of motion (unless emitted exactly along the line of motion), as long as their transverse momenta cancel each other out. Thus, they do not necessarily move along the same straight line path as the original nucleus. Reason (R) is correct because radioactive decay is a spont