An electron revolves in first orbit in H atom, then :

Options

A. Current associated due to orbital motion of electron is 1.06 m A.
B. Magnetic field at the centre of nucleus due to orbital motion of electron is 12.5 Tesla.
C. First excitation energy of H atom is 10.2 eV.
D. Current associated due to orbital motion of electron is 2.06 m A.

Explanation

To solve the problem regarding an electron revolving in the first orbit of a hydrogen atom, we will follow these steps:

### Step 1: Calculate the Excitation Energy
The excitation energy (ΔE) for an electron transitioning from the first orbit (n1 = 1) to the second orbit (n2 = 2) in a hydrogen atom can be calculated using the formula:

\[ \Delta E = 13.6 \, \text{eV} \times Z^2 \left( \frac{1}{n_1^2} - \frac{1}{n_2^2} \right) \]
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