Two coherent plane light waves of equal amplitude makes a small angle $\alpha(< < 1)$ with each other. They fall almost normally on a screen. If $\lambda$ is the wavelength of light waves, the fringe width $\Delta x$ of interference patterns of the two sets of waves on the screen is

• A

  $\frac{2 \lambda}{\alpha}$
• B

  $\frac{\lambda}{\alpha}$
• Correct answer
  C

  $\frac{\lambda}{(2 \alpha)}$
• D

  $\frac{\lambda}{\sqrt{\alpha}}$

Hence, the correct answer is option: 'C'.