Answer:
Explanation:When a railroad locomotive starts moving towards a stationary observer with velocity [tex]v_s[/tex] then apparent frequency of locomotive can be given by
[tex]f'=f\frac{v}{v-v_s}[/tex]
From above formula we can say that
apparent frequency f' is greater than actual frequency f
(b)As Frequency is increasing therefore wavelength is decreasing
as [tex]frequency\propto \frac{1}{wavelength}[/tex]
(c)Speed of sound in the air has no effect so it remains same