If young's modulus of iron be `2xx10^(11) Nm^(-2)` and interatomic distance be `3xx10^(-10) m^(-2)`, the intertomic force constant will be (in `N//m`)

Options

A. 60 N
B. 120 N
C. 3 N
D. 180 N

Answer

A

Explanation

`Y=(FL)/(Al)`
But, `(F)/(l)=K, " " ` where K is force constant
`Y=(KL)/(A)`
`K=(YA)/(L)`
If the molecules are taken to be arranged at the corners of a cube of side length L, area `A=L^(2)`.
`K=YL`
`=2xx10^(11) xx 3xx10^(-10)`
`=60N.`