Question

A nucleus of ${}_{84}^{210}Po$ originally at rest emits α particle with speed v. What will be the recoil speed of the daughter nucleus.

• A. 4v/206
• B. 4v/214
• C. v/206
• D. v/214

Answer 1

Answer: (A)

4v/206

Answer 2

$84Po^{210} \rightarrow_{82} ⥂ X^{206} +_{2} ⥂ He^{4}$

Using conservation of linear moments

$206v^{'} + 4v = 0 \Rightarrow v^{'} = - \frac{4v}{(206)} \Rightarrow |v^{'}| = \frac{4v}{206}$.