A stationary source emits sound of frequency
`upsilon=1200Hz`. If a wind blows at the speed of 0.1c deduce (i) the percentage change in the wavelength and (ii) the change in the frequency for a stationary observer on the wind side of the source. What happens when there is no wind, but the observer moves at speed 0.1c towards the source?

Explanation

To solve the problem, we need to break it down into steps. We will first find the percentage change in wavelength and then the change in frequency for a stationary observer on the wind side of the source. Finally, we will analyze the scenario where there is no wind, but the observer moves towards the source.

### Step 1: Understand the Given Information
- Frequency of the sound source, \( f = 1200 \, \text{Hz} \)
- Speed of wind, \( v_w = 0.1c \) (where \( c \) is the speed of sound in air)
- Speed of source, \( v_s = 0 \) (stationary source)
- Speed of observer, \( v_o = 0 \) (stationary observer)

...