Question

When the observer moves towards a stationary source with velocity V₁, the apparent frequency of emitted note is F₁. When observer moves away from the source with velocity V₁, the apparent frequency is F₂. If V is the velocity of sound in air and `"F"_1/"F"_2=2` then `"V"/"V"_1` is equal to ______.

Options

• 6

• 3

• 5

• 4

Answer 1

When the observer moves towards a stationary source with velocity V₁, the apparent frequency of emitted note is F₁. When observer moves away from the source with velocity V₁, the apparent frequency is F₂. If V is the velocity of sound in air and `"F"_1/"F"_2=2` then `"V"/"V"_1` is equal to 3.

Explanation:

`"F"_1=("F"("V"+"V"_1))/"V",  "F"_2=("F"("V"-"V"_1))/"V"`

`"F"_1/"F"_2=("V"+"V"_1)/("V"-"V"_1)=2`

solving `"V"/"V"_1=3`