Monochromatic radiation of wavelength `lambda` are incident on a hydrogen sample in ground state. Hydrogen atoms absorb the light and subsequently emit radiations of 10 different wavelength . The value of `lambda` is nearly :

Explanation

To solve the problem, we need to determine the wavelength \( \lambda \) of the monochromatic radiation incident on a hydrogen sample in the ground state, which results in the emission of 10 different wavelengths. Here’s how we can approach the solution step by step:

### Step 1: Understanding the Emission Lines
When hydrogen atoms absorb energy, they can transition from the ground state (n=1) to higher energy levels (n). The number of spectral lines emitted when transitioning from a higher energy level \( n \) back to lower levels can be calculated using the formula:

\[ \text{Number of lines} = \frac{n(n-1)}{2} \]
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