Question

The Young's modulus of the material of a wire is $6 \times 10 ^ { 12 } \mathrm {~N} / \mathrm { m } ^ { 2 }$ and there is no transverse strain in it, then its modulus of rigidity will be

• A. $3 \times 10 ^ { 12 } \mathrm {~N} / \mathrm { m } ^ { 2 }$
• B. $2 \times 10 ^ { 12 } \mathrm {~N} / \mathrm { m } ^ { 2 }$
• C. $10 ^ { 12 } \mathrm {~N} / \mathrm { m } ^ { 2 }$
• D. None of the above

Answer 1

Answer: (A)

$3 \times 10 ^ { 12 } \mathrm {~N} / \mathrm { m } ^ { 2 }$

Answer 2

$Y = 2 \eta ( 1 + \sigma )$

For no transverse strain

(σ = 0)

$Y = 2 \eta \Rightarrow \eta = \frac { Y } { 2 } = 3 \times 10 ^ { 12 } \mathrm {~N} / \mathrm { m } ^ { 2 }$