Q154 / 200 · MHT CET - Medical 2026 (21 April Shift 1) · Physics
The condition for observing Fraunhofer diffraction from a single slit is that the wavefront incident on a single slit must be
- Aspherical.
- Correct answerBplane.
- Ccylindrical.
- Delliptical.
Solution
In Fraunhofer diffraction, the source of light and the screen are effectively at an infinite distance from the diffracting slit.
As a result, the wavefronts of the light incident on the slit are plane wavefronts.
This is typically achieved by placing the light source at the focus of a convex lens, which converts the diverging spherical wavefronts into plane wavefronts before they strike the slit.
Thus, the incident wavefront must be plane.
Answer: plane.
As a result, the wavefronts of the light incident on the slit are plane wavefronts.
This is typically achieved by placing the light source at the focus of a convex lens, which converts the diverging spherical wavefronts into plane wavefronts before they strike the slit.
Thus, the incident wavefront must be plane.
Answer: plane.
Hence, the correct answer is option: 'B'.