Free Homi Bhabha Exam Physics Dispersion through a Prism MCQs with step-by-step solutions (5 questions). Part of Light & Optics. Practise online on Prepizo — no login needed.
Q1 — Dispersion through a Prism · medium · theory
When white light passes through a glass prism, it splits into seven colours. This phenomenon is called:
A. refraction only
B. dispersion ✓ Correct
C. diffraction
D. reflection
Solution: Dispersion is the splitting of white light into its constituent colours (VIBGYOR).
Q2 — Dispersion through a Prism · hard · theory
When white light is dispersed by a prism, the colour that bends the least is:
A. blue
B. violet
C. green
D. red ✓ Correct
Solution: Red light has the longest wavelength and is deviated least; violet is deviated most.
Q3 — Dispersion through a Prism · medium · theory
A rainbow is formed by the dispersion of sunlight by:
A. the ozone layer
B. dust particles
C. tiny water droplets in the atmosphere ✓ Correct
D. clouds reflecting light
Solution: Water droplets act like tiny prisms, dispersing sunlight into a rainbow.
Q4 — Dispersion through a Prism · hard · theory
Different colours of light are dispersed by a prism because in glass they travel at:
A. infinite speed
B. different speeds and so bend by different amounts ✓ Correct
C. the speed of sound
D. the same speed
Solution: Each colour has a slightly different speed (and refractive index) in glass, so each bends by a different amount.
Q5 — Dispersion through a Prism · medium · theory
The correct order of colours in the visible spectrum (VIBGYOR) from the least deviated to the most deviated is:
A. Red, Orange, Yellow, Green, Blue, Indigo, Violet ✓ Correct
B. Violet, Indigo, Blue, Green, Yellow, Orange, Red
C. Blue, Green, Red, Yellow, Violet, Orange, Indigo
D. Red, Yellow, Orange, Blue, Green, Violet, Indigo
Solution: Red bends least and violet most, so from least to most deviated: R, O, Y, G, B, I, V.