What pattern is observed on a screen when light passes through Young's double slits?

An interference pattern of alternating bright and dark fringes.

Explain why bright fringes form in Young's double slits experiment.

Bright fringes occur where light waves from the two slits arrive in phase and interfere constructively, reinforcing each other to produce maximum intensity.

What condition must be met for constructive interference to occur at a point on the screen in Young's experiment?

The light waves from the two slits must arrive in phase at that point.

What happens when light waves from the two slits arrive exactly out of phase at a point on the screen?

They interfere destructively, producing a dark fringe at that location.

Why can the interference pattern observed in Young's experiment only be explained by treating light as a wave?

Interference requires superposition of waves; particles cannot cancel each other out or reinforce in the way needed to produce alternating bright and dark fringes.

How did Young's double slits experiment challenge Newton's corpuscular theory of light?

It provided evidence that light behaves as a wave, which contradicted the corpuscular theory that treated light as streams of particles unable to produce interference patterns.

AQA A-Level Physics 7408

Measurements and Their Errors

Topic overview Use of SI units and their prefixes Limitation of physical measurements Estimation of physical quantities

Particles and Radiation

Topic overview Constituents of the atom Stable and unstable nuclei Particles, antiparticles and photons Particle interactions Classification of particles Quarks and antiquarks Applications of conservation laws The photoelectric effect Collisions of electrons with atoms Energy levels and photon emission Wave-particle duality

Waves

Topic overview Progressive waves Longitudinal and transverse waves Principle of superposition of waves and formation of stationary waves Interference Diffraction Refraction at a plane surface

Mechanics and Materials

Topic overview Scalars and vectors Moments Motion along a straight line Projectile motion Newton's laws of motion Momentum Work, energy and power Conservation of energy Bulk properties of solids The Young modulus

Electricity

Topic overview Basics of electricity Current–voltage characteristics Resistivity Circuits Potential divider Electromotive force and internal resistance

Further Mechanics and Thermal Physics

Topic overview Circular motion Simple harmonic motion (SHM)Simple harmonic systems Forced vibrations and resonance Thermal energy transfer Ideal gases Molecular kinetic theory model

Fields and Their Consequences

Topic overview Fields Newton's law Gravitational field strength Gravitational potential Orbits of planets and satellites Coulomb's law Electric field strength Electric potential Capacitance Parallel plate capacitor Energy stored by a capacitor Capacitor charge and discharge Magnetic flux density Moving charges in a magnetic field Magnetic flux and flux linkage Electromagnetic induction Alternating currents Transformers

Nuclear Physics

Topic overview Rutherford scattering α, β and γ radiation Radioactive decay Nuclear instability Nuclear radius Mass and energy Induced fission Safety aspects

AstrophysicsOptional topic

Topic overview Astronomical telescope consisting of two converging lenses Reflecting telescopes Single dish radio telescopes, I-R, U-V and X-ray telescopes Advantages of large diameter telescopes Classification by luminosity Absolute magnitude, M Classification by temperature, black-body radiation Principles of the use of stellar spectral classes The Hertzsprung-Russell (HR) diagram Supernovae, neutron stars and black holes Doppler effect Hubble's law Quasars Detection of exoplanets

Medical PhysicsOptional topic

Engineering PhysicsOptional topic

Topic overview Concept of moment of inertia Rotational kinetic energy Rotational motion Torque and angular acceleration Angular momentum Work and power First law of thermodynamics Non-flow processes The p–V diagram Engine cycles Second Law and engines Reversed heat engines

Turning Points in PhysicsOptional topic

Topic overview Cathode rays Thermionic emission of electrons Specific charge of the electron Principle of Millikan's determination of the electronic charge, e Newton's corpuscular theory of light Significance of Young's double slits experiment Electromagnetic waves The discovery of photoelectricity Wave–particle duality Electron microscopes The Michelson-Morley experiment Einstein's theory of special relativity Time dilation Length contraction Relativistic mass and energy

ElectronicsOptional topic

Topic overview MOSFET (metal-oxide semiconducting field-effect transistor)Zener diode Photodiode Hall effect sensor Difference between analogue and digital signals LC resonance filters The ideal operational amplifier Inverting amplifier configuration Non-inverting amplifier configuration Summing amplifier configuration Real operational amplifiers Combinational logic Sequential logic Astables Principles of communication systems Transmission media Time-division multiplexing Amplitude (AM) and frequency modulation (FM) techniques

Turning Points in Physics

Significance of Young's double slits experiment

2 things to know
Paper 3, section B

Overview

Why interference could not be explained by particles, and when wave theory was accepted.

What you need to know

Answer each one before you reveal it.

Your recallNot started

Process

What happens when waves from two slits arrive in phase and out of phase?

Process

What property did Young's experiment demonstrate, and when was wave theory accepted?

Questions from this subtopic

Each one with the model answer underneath.

1
What pattern is observed on a screen when light passes through Young's double slits?
Model answer
An interference pattern of alternating bright and dark fringes.
2
Explain why bright fringes form in Young's double slits experiment.
Model answer
Bright fringes occur where light waves from the two slits arrive in phase and interfere constructively, reinforcing each other to produce maximum intensity.
3
What condition must be met for constructive interference to occur at a point on the screen in Young's experiment?
Model answer
The light waves from the two slits must arrive in phase at that point.
4
What happens when light waves from the two slits arrive exactly out of phase at a point on the screen?
Model answer
They interfere destructively, producing a dark fringe at that location.
5
Why can the interference pattern observed in Young's experiment only be explained by treating light as a wave?
Model answer
Interference requires superposition of waves; particles cannot cancel each other out or reinforce in the way needed to produce alternating bright and dark fringes.
6
How did Young's double slits experiment challenge Newton's corpuscular theory of light?
Model answer
It provided evidence that light behaves as a wave, which contradicted the corpuscular theory that treated light as streams of particles unable to produce interference patterns.

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