Question

What is the frequency of electromagnetic waves in a vacuum that have the same wavelength as a $500.0Hz$ sound wave moving at $345m/s$?

• A. $500.0Hz$
• B. $0.690Hz$
• C. $2.30\times {10}^{-9}Hz$
• D. $1.45Hz$
• E. $4.35\times {10}^{8}Hz$

Answer 1

The correct option is E $4.35\times {10}^{8}Hz$

We know the relation $v=\lambda \nu$
Hence for waves with same wavelength,

$\frac{v_1}{{\nu }_1}=\frac{v_2}{{\nu }_2}$

$⟹{\nu }_2=\frac{v_2}{v_1}{\nu }_1$

$=\frac{3\times {10}^8}{345}\times 500Hz=4.35\times {10}^{8}Hz$