NEET Physics: Wave Optics Practice Questions
13 free multiple-choice questions on Wave Optics for NEET Physics, each with the correct answer and a step-by-step explanation. Attempt a question, then reveal the solution to check your reasoning.
Practice thousands more Wave Optics questions in the app →Q1. The intensity of the light observed at a specific point in the interference pattern depends on the phase relationship between the waves. If the phase difference between the waves is 2πn, where n is an integer, the interference will be:
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Correct answer: B — Maximum constructive interference
When the phase difference is an integer multiple of 2π (2πn), the waves are perfectly in phase, resulting in maximum constructive interference (maximum intensity).
Q2. Malus's Law states that the intensity of light transmitted through a polarizer is related to the angle between the polarizers. If the angle between the incident polarized light and the polarizer is 90°, what is the transmitted intensity?
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Correct answer: B — 0
Malus's Law is I = I₀ cos² θ. If θ= 90°, I = I₀ cos²(90°) = I₀ (0)² = 0.
Q3. The relationship between the path difference (Δx) and the phase difference (φ) of two waves is given by:
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Correct answer: B — φ= 2π(Δx / λ)
The phase difference (φ) is directly proportional to the path difference (Δx) divided by the wavelength (λ), and the full phase difference is 2π times this ratio.
Q4. What condition must be satisfied for the formation of a stable interference pattern in the double-slit experiment?
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Correct answer: D — The sources must be coherent
Interference patterns only form when the sources are coherent (same frequency and phase relationship).
Q5. The angle of incidence is defined as the angle between the incident ray and the normal at the point of incidence. Which of the following statements is true regarding the reflection of light?
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Correct answer: D — The angle of incidence is always equal to the angle of reflection.
According to the Law of Reflection, the angle of incidence (i) is always equal to the angle of reflection (r), measured with respect to the normal to the surface of incidence.
Q6. Which type of light exhibits circularly polarized waves?
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Correct answer: B — Circularly polarized light
Light that exhibits a rotation of its electric field vector in a circle is known as circularly polarized light.
Q7. Huygens' principle states that every point on a wavefront acts as a source of:
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Correct answer: B — Spherical wavelets.
Huygens' principle states that every point on a wavefront generates secondary spherical wavelets that travel into the medium.
Q8. If a wave propagates in a uniform medium, what geometric property must be maintained for the shape of the wavefront?
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Correct answer: C — Constant shape (e.g., plane, spherical, or cylindrical)
The shape of a wavefront is determined by the properties of the medium and the nature of the propagation. For simple propagation in uniform media, the wavefront maintains a specific geometric shape (like spherical or plane).
Q9. For two coherent sources producing interference, the condition for constructive interference is when the phase difference between the waves is:
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Correct answer: A — 0 or 2nπ radians
Constructive interference occurs when the phase difference between the waves is an integer multiple of 2π radians, meaning the waves are in phase.
Q10. If the speed of light in a medium is v₁ and the speed of light in another medium is v₂, and light enters the second medium, the relationship described by Snell's Law relates these speeds to the angles of incidence and refraction. Which statement accurately describes the relationship?
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Correct answer: B — The ratio of the sines of the angles is equal to the ratio of the speeds.
Snell's Law is mathematically expressed as n₁ sin i₁ = n₂ sin r₂, where n is the refractive index (n = c/v). Since n = 1/v (if c is constant), the relationship involves the ratio of the sines of the angles being proportional to the ratio of the refractive indices, which depends on the ratio of speeds.
Q11. A wave that has oscillations purely along a single direction is described as:
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Correct answer: B — Polarized wave
Polarization is a specific property of transverse electromagnetic waves, where the oscillation of the electric field is restricted to a plane, defining the polarization.
Q12. What is the value of θ when the intensity of light transmitted through a polarizer is zero, according to Malus's Law, given the incident intensity is I₀?
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Correct answer: C — θ= 90°
For the transmitted intensity I = I₀ sin²(θ) to be zero, sin²(θ) must be zero, which happens when θ= 0° or θ= 180°. In the context of polarizer angles, θ=0° means the polarizer is aligned with the polarization direction, resulting in zero transmission if the subsequent polarization is 90° relative to the first. However, based strictly on Malus's Law, I=0 occurs if sin²(θ)=0, so θ=0° (or 180°).
Q13. When the path difference between two interfering waves is an integral multiple of the wavelength, the interference will be:
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Correct answer: A — Purely constructive
Constructive interference occurs when the path difference (Δx) is an integer multiple of the wavelength (λ), i.e., Δx = nλ.
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