Correct Answer - (i) `26` (ii) `1.55 xx 10^(18) Hz`
(i) from the relation `r prop A^(1//3)`
We have `r_(1)/r_(2)=(A_(1)/A_(2))^(1//3) implies (A_(2)/4)^(1//3)=(14)^(1//3)`
`:. A_(2)=56`
(ii) `Z_(2)-A_(2)-` no. of neutrons `=56-30=26`
`:. F_(ka)=Rc (Z-1)^(2)(1/1^(1)-1/2^(2))=(3Rc)/4 (Z-1)^(2)`
Subtituting the given values of R, c and Z.
We get `f_(ka)=1.55xx10^(18) Hz`