Physical World Units and Measurements - Result Question 20

21. The dimensions of Planck’s constant are same as

(a) energy

[2001]

(b) power

(c) momentum

(d) angular momentum

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Answer:

Correct Answer: 21. (d)

Solution:

  1. (d) We know that $E=h v$

$h=\frac{E}{v}=\frac{[ML^{2} T^{-2}]}{[T^{-1}]}=[ML^{2} T^{-1}]$

Angular momentum $=I \omega$

$=[ML^{2}][T^{-1}]=[ML^{2} T^{-1}]$

(c) Force has dimension $[MLT^{-2}]$ while impulse has dimension $[MLT^{-1}]$, both have different dimensions.