Question

$Y,K,$$\eta$ represent respectively the young's modulus, bulk modulus and rigidity modulus of a body. If young's modulus is twice the bulk modulus, then :

• A. $\eta =$ 6K/7
• B. $\eta =$ 7K/9
• C. $\eta =$ 9K/7
• D. Y $=$ 18K/7

Answer 1

Answer: (A)

$\eta =$ 6K/7

According to relation between young's modulus,bulk modulus and modulus of rigidity
$Y=\frac{9\eta K}{3K+\eta }$
$Y=2K$
If we sub situate this value of $Y=2$ K in the formula of "$Y$"
then we will get $\eta =\frac{6K}{7}$