JEE Main 2022 · 28 Jun · Shift 1 · Physics Q31

PhysicsSingle correct+4 / -1Question 31 of 90

Given below are two statements : One is labelled as Assertion A and the other is labelled as Reason R.

Assertion A : Product of Pressure (P) and time (t) has the same dimension as that of coeffcient of viscosity.

Reason R : Coefficient of viscosity $=\dfrac{\text{Force}}{\text{Velocity gradient}}$

Choose the correct answer from the options given below :

Both A and R true, and R is correct explanation of A.

Both A and R are true but R is NOT the correct explanation of A.

A is true but R is false.

A is false but R is true.

Answer and worked solution

Official answer: C

Assertion. $[Pt]=ML^{-1}T^{-2}\cdot T=ML^{-1}T^{-1}$ , the dimension of viscosity: true.

Reason. Viscosity is $\dfrac{\text{Force}}{\text{Area}\times\text{velocity gradient}}$ ; without the area the statement is false.

(C)

Topics:Dimensional analysis Viscosity and Stokes' law

JEE Main 2022 · 28 Jun · Shift 1, Physics question 31