Question

Define modulus of elasticity, stress, strain and Poisson's ratio.

Answer 1

Modulus of elasticity : it is the ratio of stress applied on a body to the strain produced in the body.

e.g., Y = stress/strain so, si unit of modulus of elasticity is N/m² or Pascal

Stress : when a body is subjected to an external force, the force per unit area is called stress.
so, stress = force/area = F/A . So, si unit of stress is N/m² or Pascal

Poisson's ratio : it is the ratio of lateral strain to longitudinal strain of a body .
e..g., Poisson's ratio = lateral strain/longitudinal strain = $\frac{-\Delta r/r}{\Delta L/L}$
It is clear that , Poisson's ratio is dimensionless quantity.

Answer 2

Explanation:

State the safety measures in using electricity.