Question

If P,Q,R are the physical quantities, having different dimensions, which

of the following combinations can never be a meaningful quantity?

(a) (P – Q)/R

(b) PQ – R

(c) PQ/R




(d) (PR – Q2)/R




(e) (R + Q)/P

Answer 1

options (a) (e) are the correct choices.

explanation :- according to rule of dimension, we know , two different dimensional quantities can't be added or subtracted. while both quantities can be multiplied as well as divided.

for example :- we can't add velocity and displacement because of velocity and displacement are two different quantities of different dimensions.
so, velocity + displacement = doesn't exist.

hence, option (a) and (e) are correct