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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 coefficient of viscosity. Reason R: Coefficient of viscosity =(Force)/(Velocity gradient). Choose the correct answer from the options given below.

Asked in JEE Main 28th June 1st Shift 2022 · Pairs with the same dimensions

Answer: (3) A is true but R is false.

Step-by-step solution

Assertion: Pt=[ML⁻¹T⁻²][T]=[ML⁻¹T⁻¹], which is the dimension of viscosity. True.

Reason: the definition is η=F/(A (dv/dx)), with the area in the denominator.

Dropping the area gives ([MLT⁻²])/([T⁻¹])=[MLT⁻¹], which is not a viscosity. False.

So A is true but R is false.

Why the other options are wrong

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