Question

The angular momentum for the electron in Bohr’s orbit is L. If the electron is assumed to revolve in second orbit of hydrogen atom, then the change in angular momentum will be

• A. L
• B. 1L
• C. 2L
• D. 1.5L

Hint:

In Bohr’s model, angular momentum is quantized: L_n = nh. The change in an gular momentum between orbits is simply the difference in their quantized values.

Answer 1

The Correct Option is A

Step 1: Formula for Angular Momentum

The angular momentum is given by:

\( L = \frac{nh}{2\pi} \)

Where:

• \( n \): Principal quantum number
• \( h \): Planck's constant

Step 2: Calculate \( L_1 \) for \( n = 1 \)

Substitute \( n = 1 \):

\[ L_1 = \frac{1 \cdot h}{2\pi} = L \]

Step 3: Calculate \( L_2 \) for \( n = 2 \)

Substitute \( n = 2 \):

\[ L_2 = \frac{2 \cdot h}{2\pi} = 2L \]

Step 4: Calculate Change in Angular Momentum (\( \Delta L \))

The change in angular momentum is:

\[ \Delta L = L_2 - L_1 = 2L - L = L \]

Conclusion:

The change in angular momentum is \( \Delta L = L. \)