The mass of hydrogen molecule is `3.32xx10^(-27)` kg. If `10^(23)` hydrogen molecules strikes per second at 2 `cm^(2)` area of a rigid wall at an angle of `45^(@)` from the normal and rebound back with a speed of 1000 `ms^(-1)`, then the pressure exerted on the wall is

Options

A. `4.7 xx 10^(-24) kg ms^(-1)`
B. `7.4 xx 10^(-24) kg ms^(-1)`
C. `3.32 xx 10^(-24) kg ms^(-1)`
D. `2.33 kg ms^(-1)`

Answer

A

Explanation

Change in momentum
= ` 2"mv" "cos"(45^(@))`
= `2 xx 3.32 xx 10^(-24) xx 10^(3) xx (1)/(sqrt(2))`
= `4.7 xx 10^(-24) kg ms^(-1)`,