Single Choice

In producing a pure spectrum, the incident light is passed through a narrow slit placed in the focal plane of an achromatic lens because a narrow slit

Aproduce less diffraction
Bincrease intensity
Callows only one colour at a time
Dallows a more parallel beam when it passes through the lens.
Correct Answer

Solution

If the slit is wide, different part of the slit produces different spectra, which overlap resulting in impure spectrum. Therefore narrow slit is used as it allows more parallel beam of light when it passes through the lens.

SIMILAR QUESTIONS

Wave Optics

The bending of light near the edges of an obstacle and spreading into the region of geometrical shadow is called ___________.

Wave Optics

To observe diffraction, the size of an obstacle:

Wave Optics

Answer the following questions: (a) In a single slit diffraction experiment, the width of the slit is made double the original width. How does this affect the size and intensity of the central diffraction band? (b) In what way is diffraction from each slit related to the interference pattern in a double-slit experiment? (c) When a tiny circular obstacle is placed in the path of light from a distant source, a bright spot is seen at the centre of the shadow of the obstacle. Explain why? (d) Two students are separated by a 7 m partition wall in a room 10 m high. If both light and sound waves can bend around obstacles, how is it that the students are unable to see each other even though they can converse easily. (e) Ray optics is based on the assumption that light travels in a straight line. Diffraction effects (observed when light propagates through small apertures/slits or around small obstacles) disprove this assumption. Yet the ray optics assumption is so commonly used in understanding location and several other properties of images in optical instruments. What is the justification?

Wave Optics

To observe diffraction, the size of the obstacle

Wave Optics

When a compact disc is illuminated by small source of white light, coloured bands are observed. This is due to

Wave Optics

Diffraction effects are more easily detected in the case of sound waves than light waves because:

Wave Optics

The diffraction effect can be observed in

Wave Optics

The bending of beam of light around corners of obstacles is called

Wave Optics

The penetration of light into the region of geometrical shadow is called

Contact Details