In rutherford's experiment, the mumber of alpha-particles scattered through an angle of `90^(@)` is 28 per minute. Then,the number of particles scattered through an angle of `60^(@)`per minute by the same nucleus is

Options

A. 28 per minute
B. 112 per minute
C. 12.5 per minute
D. 7 per minute

Answer

B

Explanation

`N prop (1)/(sin^(4)((theta)/(2)))`
`(N_(1))/(N_(2)) = ((sintheta_(2)//2)/(sintheta_(1)//2))^(4)=((sin30^(@))/(sin45^(@)))=(1)/(4)`
`N_(2)=4N_(1)= 112` per minute `(N_(1) = 28` per minute)