Explain the construction of a spherical wavefront by using Huygens' principle.
Derive an expression for the equation of stationary wave on a stretched string. Show that the distance between two successive nodes or antinodes is \( \frac{\lambda}{2} \).
Two tuning forks having frequencies 320 Hz and 340 Hz are sounded together to produce sound waves. The velocity of sound in air is 340 m/s. Find the difference in wavelength of these waves.