AP EAMCET Engineering 23 Sep 2020 Shift 1 Paper

Given that, source is stationary, vs=0
Assume, velocity of observer v0 and that of sound in air is v and true frequency of sound is v0.
Heard frequency, v=1% higher than true frequency
v=1.01v0
From Doppler's effect, if source is stationary and observer is moving towards source along a line joining them. Then, expression of heard frequency is given by
v=(‌

v+ve

v

)v0
or ‌

v

v0

=‌

v+vo

v

or 1.01=‌

v+vo

v

or 1.01v‌‌=v+v0
or 0.01v‌‌=v0
or ‌

vo

v

‌‌=0.01
or ‌

vo

v

‌‌=‌

1

100