A tuning fork having n = 300 Hz produces 5 beats/s with another tuning fork. If impurity (wax) is added on the arm of known tuning fork, the number of beats decreases then calculate the frequency of unknown tuning fork.

Explanation

To solve the problem, we need to determine the frequency of the unknown tuning fork based on the information given about the beats produced when it is played with a known tuning fork of frequency 300 Hz.

### Step-by-Step Solution:

1. **Understanding Beats**:
- The number of beats produced when two tuning forks are played together is equal to the absolute difference in their frequencies.
- If the known tuning fork has a frequency \( f_1 = 300 \, \text{Hz} \) and the unknown tuning fork has a frequency \( f_2 \), then the number of beats per second is given by:
\[
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