Question

The picture shows a wave generated in a laboratory. If the frequency of the wave shown were doubled, the wavelength of the wave would become :

• A. 0.85 cm
• B. 1.35 cm
• C. 3.4 cm
• D. 5.4 cm

Answer 1

The correct option is A 0.85 cm

The wavelength is the distance travel for a complete cycle. Here in the figure , the wave starts at 1 cm and go back to same position at 2.7 cm and the it will repeat the pattern.

So the wavelength will be, $\lambda =2.7-1=1.7cm$

We know that $v=f\lambda$

As velocity of speed is constant so $\lambda \propto 1/f$

When f is doubled, the wavelength will be half.

so the required wavelength $=1.7/2=0.85$ cm