`10^(23)` molecules of a gas strike a target of area `1 m^(2)` at angle `45^(@)C` to normal and rebond elastically with speed `1 kms^(1)`. The impulses normal to wall per molecule is " - [Given : mass of molecule = `3.32 xx 10 ^(-27)kg`]

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)`,