Exams › NEET › Physics

The same slit is illuminated by another monochromatic light, the angular width decreases by 30%. The wavelength of this light is

1. 420 Å
2. 1800 Å
3. 4200 Å
4. 6000 Å

Correct answer: 4200 Å

Solution

The angular width of a single-slit diffraction pattern is directly proportional to the wavelength of light. If the angular width decreases by 30%, the new wavelength is 70% of the original. Assuming the original wavelength is 6000 Å, the new wavelength is 0.7 × 6000 Å = 4200 Å.

Related NEET Physics questions

• Ray optics is valid when characteristic dimension are
• In Young's experiment with white light, the central fringe is white. If now a transparent film is introduced in the upper beam coming from the top slit, then the white fringe:
• A: Coloured spectrum is seen when we look through a cloth R: Diffraction of light takes place when light is travelling through the pores of cloth
• A microscope is used with sodium light and its resolving power is not sufficiently large.Higher resolution will be obtained by using wavelength of
• Assertion Assertion: When a light wave travels from a rarer to a denser medium, its speed decreases. The decrease in speed imply a reduction in energy carried by the light wave. Reason Reason: The energy of a wave is inversely proportional to velocity of wave
• When light travels from one medium into another it suffers

⚔️ Practice NEET Physics free + battle 1v1 →