Question:

Which pair of physical quantities have same dimensional formula?

Show Hint

Stress, pressure and modulus of elasticity have the same dimensional formula \(ML^{-1}T^{-2}\).
  • Torque and momentum
  • Surface tension and tension
  • Pressure and modulus of elasticity
  • Force constant and Planck's constant
Show Solution
collegedunia
Verified By Collegedunia

The Correct Option is C

Solution and Explanation

Concept:
Two physical quantities have the same dimensional formula when they are expressed using the same powers of mass, length and time.

Step 1:
Pressure is defined as force per unit area: \[ P=\frac{F}{A} \]

Step 2:
Dimension of force is: \[ [F]=MLT^{-2} \]

Step 3:
Dimension of area is: \[ [A]=L^2 \]

Step 4:
Therefore, dimension of pressure is: \[ [P]=\frac{MLT^{-2}}{L^2}=ML^{-1}T^{-2} \]

Step 5:
Modulus of elasticity is defined as: \[ \text{Modulus}=\frac{\text{stress}}{\text{strain}} \]

Step 6:
Strain is dimensionless, and stress has the same dimension as pressure. \[ [\text{Modulus of elasticity}]=ML^{-1}T^{-2} \]

Step 7:
Hence pressure and modulus of elasticity have the same dimensional formula. \[ \boxed{\text{Pressure and modulus of elasticity}} \]
Was this answer helpful?
0
0