Question

With what velocity an observer should move relative to a stationary source so that a sound of double the frequency of source is heard by an observer?

Options

• Same as velocity of sound towards the source

• Twice the velocity of sound towards the source

• Half the velocity of sound towards the source

• Same as velocity of sound away from the source

Answer 1

Same as velocity of sound towards the source

Explanation:

`"v"^'="v"(("v"+"v"_0)/"v")="v"(1+"v"_0/"v")`

v' = 2v

`therefore2"v"="v"(1+"v"_0/"v")`

`therefore2=1+"v"_0/"v"`

`therefore"v"_0/"v"=1`

∴ v₀ = v