The `6563 Å H_(2)` line emitted by hydrogen in a star is found to be red shifted by `15 Å`. Estimate the speed with which the star is receding from earth.

Explanation

To solve the problem of estimating the speed with which the star is receding from Earth based on the redshift of the H₂ line, we can follow these steps:

### Step 1: Identify the Given Values
We have the following values:
- Original wavelength of the H₂ line, \( \lambda = 6563 \, \text{Å} \)
- Redshift in wavelength, \( \Delta \lambda = 15 \, \text{Å} \)

### Step 2: Calculate the Observed Wavelength
...