Question

The SI unit of stress is same as the SI unit of

• A. Strain
• B. Pressure
• C. Modulus of elasticity
• D. Both (B) and (C)

Answer 1

The correct option is C

Modulus of elasticity

The explanation for the correct option:

In the case of option B,

1. Stress is defined as the force applied to a material's unit area. The consequence of stress on the body is known as strain. Structural deformation can happen as a consequence of stress.
2. SI unit of stress is Pascal, $Pa$.

Stress can be calculated by, $\sigma =\frac{F}{A}$

Where,

$\sigma$ is Stress.

$F$ is Force.

$A$is Area.

SI unit of force ($F$) is Newton $\left(N\right)$ and $A$ is meter square $\left(m^2\right)$.

$\sigma =\frac{N}{m^2}$

$\Rightarrow \frac{N}{m^2}=Pa$

SI unit of Stress is $Pa$.

Pressure can be calculated by, $P=\frac{F}{A}$

Where,

$P$ is Pressure.

$F$ is Force.

$A$is Area.

In the case of option C (modulus of elasticity),

1. The proportion of a body's stress to its equivalent strain is called the modulus of elasticity.
2. Formula: $\mathrm{\lambda }=\frac{\mathrm{Stess}}{\mathrm{Strain}}$.
3. The SI unit is ${\mathrm{Nm}}^{-2}$.

The explanation for the incorrect options:

In the case of option A (strain),

1. The proportion of change in form or size to the initial shape and size is called strain.
2. The strain doesn't have any unit.

Therefore, the correct option is B&C.