Concepts Of Physics MCQ Edition [Volume 2]PhysicsCalorimetry
Which of the following is true for the mechanical equivalent of heat?
Options
- AIt possesses the same dimensions as work.
- BIt possesses the same dimensions as heat.
- CIt possesses the same dimensions as energy.
- DIt is a dimensionless quantity.
Correct answer
D. It is a dimensionless quantity.
Step-by-step solution
According to the relation between work and heat, W = JH , where W is work, H is heat, and J is the mechanical equivalent of heat. Rearranging the formula, J = W H . Since both work and heat are forms of energy, their dimensional formulas are the same, which is [M L^2 T⁻²] . Substituting the dimensions, [J] = [M L^2 T⁻²] [M L^2 T⁻²] = [M^0 L^0 T^0] . Therefore, the mechanical equivalent of heat is a dimensionless quantity.