Mark the wrong statement

Options

A. Sliding of molecular layer is much easier than compression or expansion.
B. Reciprocal of bulk modulus of elasticiy is called compressibility
C. It is difficult to twist a long rod as compared to small rod.
D. Hollow shaft is much stronger than a solid rod of same length and same mass.

Answer

C

Explanation

(c) `Deltal=(FL)/(pir^(2)Y)`
`implies r^(2) prop (1)/(Y)" "`[F, L and `Deltal` are constant]
`(r_(2))/(r_(1))=((Y_(1))/(Y_(2)))^(1//2)=((7xx10^(10))/(0.2xx10^(10)))^(1//2)`
`implies` Radius `r_(2)=1.5xx((7)/(12))^(1//2)=1.145 mm`
`therefore d=2.29 mm`