COMEDK Exam 2022 Solved Paper

According to Doppler's effect, the apparent frequency of sound when both source and observer are moving towards each other
⇒ f=

(v+v0)f0

(v−v0)

⇒ f=(

v

v−vs

)f0+(

v0

v−vs

)f0
⇒ f=(

f0

v−vs

)v0+(

f0

v−vs

)v
Equation of straight line, y=mx+c which is equation of straight line making an intercept c on Y-axis,
Slope of the graph =

f0

v−vs

and intercept =

vf0

v−vs

This condition is represented in graph A plotted between f and v0.
Hence, option (c) is correct.