AP EAPCET 05-Jul-2022 Shift 1 Paper

Here, both cars are moving towards each other, hence one car is like an observer and another car is like a source .
∴‌‌vs=50m∕ s⇒v0=−50m∕ s
Frequency of horn blown by the source car,
v=250‌Hz
According to Doppler's effect, frequency heard by another car v′ is given as
v′=‌

v−v0

v−v3

×v=‌

350−(−50)

350−50

×250
‌∴(v=‌ speed of sound ‌=350m∕ s)
‌‌‌‌‌=‌

400×250

300

⇒v′=‌

100

3

‌Hz
Wavelength of heard sound,
λ′‌=‌

v

v′

‌=‌

350

1000∕3

=‌

1050

1000

=1.05m=105‌cm