Due to the shape of the lens , parallel rays will be deviated
Answer:
f' = 3665.51 Hz
Explanation:
given,
speed of the hawk = 24.7 m/s
frequency of screech emitted by the hawk = 3400 Hz
speed of sound = 331 m/s
By Doppler's effect

f' is the frequency received by the mouse
v is the speed of the sound
v_s is the speed of the hawk
now,

f' = 1.078 x 3400
f' = 3665.51 Hz
The frequency received by the stationary mouse is equal to 3665.51 Hz
You have to cross multiply. So set up the equation like 1.6/x = 1/65 then multiply x by 1 and 1.6 by 65. The answer is 104 km/h.