Young Double Slit Quiz: Test Your Light Interference Knowledge

10th Grade

Reviewed by Ekaterina Yukhnovich

Ekaterina Yukhnovich, PhD |

Science Expert

Review Board Member

Ekaterina V. is a physicist and mathematics expert with a PhD in Physics and Mathematics and extensive experience working with advanced secondary and undergraduate-level content. She specializes in combinatorics, applied mathematics, and scientific writing, with a strong focus on accuracy and academic rigor.

, PhD

By Thames

Thames

Community Contributor

Quizzes Created: 10017 | Total Attempts: 9,652,179

| Questions: 20 | Updated: Mar 13, 2026

Share on Facebook Share on Twitter Share on Whatsapp Share on Pinterest Share on Email Copy to Clipboard Embed on your website

Question 1 / 21

🏆 Rank #-- ▾

0 %

0/100

Score 0/100

1. In Young’s double-slit experiment, the two slits act like:

Two mirrors only

Two coherent wave sources

Two lenses only

Two absorbers

Concept: two-slit sources. Light emerging from each slit spreads like a wave. The two waves overlap on the screen to create fringes.

Explanation

Concept: two-slit sources. Light emerging from each slit spreads like a wave. The two waves overlap on the screen to create fringes.

Submit

About This Quiz

Young Double Slit Quiz: Test Your Light Interference Knowledge - Quiz

This assessment explores the principles of light interference through the double slit experiment. It evaluates your understanding of wave behavior, diffraction, and the fundamental concepts of quantum mechanics. Engaging with this content enhances your grasp of optical phenomena, making it relevant for students and enthusiasts aiming to deepen their knowledge... see morein physics. see less

2. What first name or nickname would you like us to use?

You may optionally provide this to label your report, leaderboard, or certificate.

2. Bright fringes occur where the waves from the two slits arrive in phase.

True

False

Concept: constructive condition. In-phase arrival means crests align with crests. That produces higher amplitude and brighter intensity.

Explanation

Concept: constructive condition. In-phase arrival means crests align with crests. That produces higher amplitude and brighter intensity.

Submit

3. The main reason fringes appear is that different points on the screen have different:

Light speeds in vacuum

Path differences from the two slits

Source temperatures

Screen materials

Concept: path difference creates phase difference. Different screen points are different distances from each slit. That changes phase difference and thus brightness.

Explanation

Concept: path difference creates phase difference. Different screen points are different distances from each slit. That changes phase difference and thus brightness.

Submit

4. A bright fringe occurs when path difference equals an ______ multiple of the wavelength.

Concept: constructive path condition. If the path difference is (m\lambda), the waves line up in phase. This yields constructive interference.

Explanation

Concept: constructive path condition. If the path difference is (m\lambda), the waves line up in phase. This yields constructive interference.

Submit

5. A dark fringe occurs when path difference is closest to:

(m\lambda)

((m+1/2)\lambda)

(2m\lambda) only

0 always

Concept: destructive path condition. Half-integer multiples of wavelength produce a 180° phase shift. This aligns crest with trough and cancels intensity.

Explanation

Concept: destructive path condition. Half-integer multiples of wavelength produce a 180° phase shift. This aligns crest with trough and cancels intensity.

Submit

6. The central bright fringe is located where the path difference is zero.

True

False

Concept: central maximum. At the centreline, the distances from the two slits are equal. Equal path lengths mean in-phase addition.

Explanation

Concept: central maximum. At the centreline, the distances from the two slits are equal. Equal path lengths mean in-phase addition.

Submit

7. If you increase the slit separation (slits farther apart), the fringe spacing on the screen generally:

Increases

Decreases

Stays the same

Becomes random

Concept: slit separation effect. Larger slit separation makes the angle changes required for each bright fringe smaller. That brings fringes closer together.

Explanation

Concept: slit separation effect. Larger slit separation makes the angle changes required for each bright fringe smaller. That brings fringes closer together.

Submit

8. Using red light instead of blue light (same setup) typically makes the fringes more widely spaced.

True

False

Concept: wavelength effect. Red light has a longer wavelength than blue. Longer wavelength generally increases fringe spacing.

Explanation

Concept: wavelength effect. Red light has a longer wavelength than blue. Longer wavelength generally increases fringe spacing.

Submit

9. If one slit is blocked, the pattern becomes:

A stronger double-slit pattern

A single-slit pattern without two-source interference fringes

More dark fringes

Completely dark everywhere

Concept: need two paths. Two-slit interference requires two coherent contributions. With one slit blocked, the two-source interference disappears.

Explanation

Concept: need two paths. Two-slit interference requires two coherent contributions. With one slit blocked, the two-source interference disappears.

Submit

10. For stable fringes, the light used should have:

Random phase changes

Coherence

No wavelength

Infinite intensity

Concept: coherence for stability. A stable phase relationship keeps the pattern from washing out. Lasers are commonly used for this reason.

Explanation

Concept: coherence for stability. A stable phase relationship keeps the pattern from washing out. Lasers are commonly used for this reason.

Submit

11. Fringe contrast decreases if the two slits have very different intensities.

True

False

Concept: visibility and balance. If one wave is much weaker, cancellation is incomplete and maxima/minima become less distinct. Similar amplitudes give higher contrast.

Explanation

Concept: visibility and balance. If one wave is much weaker, cancellation is incomplete and maxima/minima become less distinct. Similar amplitudes give higher contrast.

Submit

12. Interference minima are also called dark ______.

Concept: fringe naming. Minima correspond to destructive interference. They appear as dark fringes on the screen.

Explanation

Concept: fringe naming. Minima correspond to destructive interference. They appear as dark fringes on the screen.

Submit

13. The main “wave property” revealed by double-slit interference is:

Mass of photons

Superposition and phase

Electric charge of light

Heat conduction

Concept: superposition evidence. The pattern is explained by adding waves with different phase relationships. This is a core wave behaviour.

Explanation

Concept: superposition evidence. The pattern is explained by adding waves with different phase relationships. This is a core wave behaviour.

Submit

14. Path difference and phase difference are directly related because phase depends on how many wavelengths fit into a path.

True

False

Concept: phase–path link. A full wavelength difference returns the wave to the same phase. A half-wavelength difference flips it to opposite phase.

Explanation

Concept: phase–path link. A full wavelength difference returns the wave to the same phase. A half-wavelength difference flips it to opposite phase.

Submit

15. If the wavelength is shortened (same geometry), fringes become:

More widely spaced

More closely spaced

Unchanged

Only brighter

Concept: shorter wavelength compresses fringes. Smaller wavelength means the condition (m\lambda) is met more frequently with position change. That reduces fringe spacing.

Explanation

Concept: shorter wavelength compresses fringes. Smaller wavelength means the condition (m\lambda) is met more frequently with position change. That reduces fringe spacing.

Submit

16. Which best describes coherence?

Having the same colour only

Maintaining a stable phase relationship

Having the same brightness only

Having no frequency

Concept: coherence definition. Coherence is about phase stability over time and distance. It’s essential for clear interference.

Explanation

Concept: coherence definition. Coherence is about phase stability over time and distance. It’s essential for clear interference.

Submit

17. Interference fringes are a result of intensity adding directly (brightness + brightness).

True

False

Concept: fields add, not intensities. The electric fields (amplitudes) add first; intensity depends on the square of the resulting amplitude. This is why phase matters so much.

Explanation

Concept: fields add, not intensities. The electric fields (amplitudes) add first; intensity depends on the square of the resulting amplitude. This is why phase matters so much.

Submit

18. A half-wavelength path difference corresponds to a phase difference of ______ degrees.

Concept: phase from path difference. Half a wavelength shifts the wave by half a cycle. Half a cycle is 180°, which produces destructive interference.

Explanation

Concept: phase from path difference. Half a wavelength shifts the wave by half a cycle. Half a cycle is 180°, which produces destructive interference.

Submit

19. The alternating bright and dark bands on the screen are called:

Refractions

Echoes

Fringes

Diffusions

Concept: fringe terminology. Interference patterns are described using fringes. Bright fringes are maxima; dark fringes are minima.

Explanation

Concept: fringe terminology. Interference patterns are described using fringes. Bright fringes are maxima; dark fringes are minima.

Submit

20. The double-slit experiment demonstrates that even when light is very weak, it still shows wave-like interference behaviour.

True

False

Concept: robust wave signature. Interference is a fundamental signature of wave superposition. The pattern reflects phase relationships, not just brightness.

Explanation

Concept: robust wave signature. Interference is a fundamental signature of wave superposition. The pattern reflects phase relationships, not just brightness.

Submit