`""^(60 m)Co rarr ^(60)`Co emits `gamma`- radiations of wavelength `3 xx 10^(-10)`m. Assuming each nuclei emits one wavelength, with what mass per mole of two nuclei differ ?

Options

A. `4.43 xx 10^(-9)` g
B. `4.43 xx 10^(-6)`g
C. `4.43 xx 10^(-3)` g
D. 4.43 g

Answer

B

Explanation

E/photon ` = (N.hc)/(lambda)` Also, `E = mc^(2) " "therefore " " (N.hc)/(lambda) = mc^(2)`
`therefore m = (N.h)/(c.lambda) = (6.02 xx 10^(23) xx 6.626 xx 10^(-34))/(3 xx 10^(8) xx 3 xx 10^(-10)) = 4.43 xx 10^(-9)` kg `= 4.43 xx 10^(-6)` g