Question

Which of the following is unitless quantity?

• A. Pressure gradient
• B. Displacement gradient
• C. Force gradient
• D. Velocity gradient

Answer 1

Answer: (B)

Displacement gradient

The gradient of any physical quantity is computed to as per unit length. This means it is a rate with respect to length. So, the Displacement gradient will also be length per unit length. Because a displacement gradient is the ratio of two quantities having dimensions of "length". That is, a displacement gradient has units of a meter per meter for example.

The length dimensions will be cancelled, and we have a unitless quantity. While others will be having certain units. Hence it is a unitless quantity.

Thus option B is correct.