Concepts Of Physics MCQ Edition [Volume 1]PhysicsSome Mechanical Properties of Matter
As a metal wire is stretched by a load, the fractional change in its volume V V is proportional to
Options
- Al l
- B( l l )^2
- Cl l
- Dl l
Correct answer
D. l l
Step-by-step solution
Volume of a cylindrical wire is V = r^2 l Differentiating to find the fractional change in volume: V V = 2 r r + l l Poisson's ratio is defined as = - r / r l / l r r = - l l Substituting this into the expression for fractional change in volume: V V = -2 l l + l l = (1 - 2 ) l l Since is a constant for a given material, (1 - 2 ) is constant. Therefore, V V l l