Question

5. In the radioactive decay of U233, the center
of the emerging ,He particles is at a certain
distance 12 x 10-15 m from the center of
residual Th234 nucleus at that instant. The
force on the helium atom is
(A) 222 N (B) 300 N
(C) 288N (D) 258 N​

Answer 1

In the radioactive decay of U233, the center of the emerging ,He particles is at a certain distance 12 x 10-15 m from the center of residual Th234 nucleus at that instant. The force on the helium atom is

(A) 222 N (B) 300 N

(A) 222 N (B) 300 N(C) 288N (D) 258 N

answer : option (D) 258 N

explanation : charge on each He particle q = 2e

charge on Th234 nucleus, Q = 81e

distance between He and Th nuclei , r = 12 × 10^-15 m

from Coulomb's law,

F = kqQ/r²

= (9 × 10^9)(2e)(81e)/(12 × 10^-15)²

= (9 × 162 × 10^9 × e²)/(144 × 10^-30)

= (9 × 162 × 2.56 × 10^-29)/(144 × 10^-30)

= 259.2 N

it is nearest value of 258 N. hence, option (D) is correct choice.