Assertion (A) Energy per unit volume and angular momentum can be added dimensionally. Reason (R) Physical…
Assertion (A) Energy per unit volume and angular momentum can be added dimensionally.
Reason (R) Physical quantities having same dimensions can be added or subtracted.
Both (A) and (R) are true and (R) is the correct explanation of (A)
Both (A) and (R) are true but (R) is not the correct explanation of (A)
(A) is true but (R) is false
(A) is false but (R) is true
Solution
The units of energy per unit volume is $\mathrm{J} / \mathrm{m}^3$ or $\mathrm{kg} / \mathrm{m}-\mathrm{s}^2$ and that for angular momentum is $\mathrm{kg}-\mathrm{m}^2 / \mathrm{s}$.
Since, they are not dimensionally equal, they cannot be added, so the Assertion (A) is false. Only those physical quantities that have same dimensions can be added or subtracted, so Reason (R) is true.
Hence, the correct option is $(\mathrm{d})$.