Question

Which of the following is an integral multiple of $\dfrac{h}{2\pi}$ in Bohr's model of an hydrogen atom?

• A. Radius of an atom
• B. Kinetic energy
• C. Potential energy
• D. Angular momentum

Hint:

Bohr quantisation: angular momentum is n h over 2 pi.

Answer 1

The Correct Option is D

Step 1: Approach
Recall the quantisation condition and test each option's units.

Step 2: Units
$\dfrac{h}{2\pi}$ has the units of angular momentum (J s). Radius is in metres and energies are in joules, so they cannot be integer multiples of it.

Step 3: Answer
Only angular momentum qualifies: option (D).

Final Answer:
Bohr's rule fixes the angular momentum at n h over 2 pi, option (D). \[ \boxed{\text{Angular momentum}} \]