NEET UG Physics Practice Paper – Wave Optics (Set 13)

Attempt all 30 MCQs and check your score instantly.

1. Interference occurs due to:

superposition
reflection
refraction
none

2. Constructive interference condition:

path difference = nλ
nλ/2
zero only
none

3. Destructive interference:

(2n+1)λ/2
nλ
λ
none

4. Young’s double slit experiment shows:

wave nature
particle
dual
none

5. Fringe width formula:

λD/d
D/λd
λ/d
none

6. Coherent sources have:

same phase
same amplitude
same speed
none

7. Diffraction occurs due to:

bending of light
reflection
refraction
none

8. Single slit diffraction minimum:

a sinθ = nλ
λ/a
none
zero

9. Central maximum is:

widest
narrow
same
none

10. Polarization proves:

transverse nature
longitudinal
both
none

11. Brewster angle formula:

tanθ = n
sinθ
cosθ
none

12. Fringe width increases with:

wavelength
slit width
none
zero

13. Fringe width decreases with:

slit separation
wavelength
D
none

14. Diffraction depends on:

wavelength
speed
charge
none

15. Coherence requires:

fixed phase
variable phase
none
zero

16. Fringe width unit:

meter
second
Hz
none

17. Light speed in vacuum:

3×10⁸ m/s
10⁶
10⁵
none

18. Interference fringes are:

equally spaced
random
unequal
none

19. Diffraction pattern central maxima:

brightest
dim
zero
none

20. Path difference unit:

meter
second
Hz
none

21. Polarizer reduces intensity:

yes
no
infinite
none

22. Unpolarized light:

random vibrations
fixed
none
zero

23. Intensity ∝ amplitude:

square
linear
none
zero

24. Wavelength unit:

meter
second
Hz
none

25. Diffraction prominent when:

slit ~ wavelength
slit large
none
zero

26. Phase difference unit:

radian
meter
second
none

27. Interference requires:

coherence
reflection
none
zero

28. Diffraction pattern width:

inversely slit
direct slit
none
zero

29. Light nature:

wave
particle
dual
none

30. Interference intensity max when:

waves in phase
out phase
none
zero

Submit

NEET UG Physics Notes – Wave Optics (Set 13)

Wave Optics is a concept-heavy and highly scoring chapter in NEET UG Physics. It explains the wave nature of light through phenomena like interference, diffraction, and polarization. Questions are usually direct formula-based or concept-based, making it a reliable scoring area.

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1. Wave Nature of Light

Light behaves as a wave in many phenomena.

Key Evidence:

• Interference
• Diffraction
• Polarization

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2. Principle of Superposition

When two waves overlap, their displacements add up.

Result:

• Constructive interference
• Destructive interference

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3. Interference of Light

Interference is the redistribution of intensity due to superposition.

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4. Conditions for Interference

Constructive Interference:

$$\text{Path difference} = n\lambda$$Path difference=nλ

Destructive Interference:

$$\text{Path difference} = \frac{(2n+1)\lambda}{2}$$Path difference=2(2n+1)λ​

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5. Young’s Double Slit Experiment (YDSE)

Important Formula:

$$\beta = \frac{\lambda D}{d}$$β=dλD​

Where:

• $\beta$β = fringe width
• $D$D = distance to screen
• $d$d = slit separation

Key Observations:

• Fringes are equally spaced
• Central fringe is bright

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6. Coherent Sources

Sources are coherent if:

• Same frequency
• Constant phase difference

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7. Factors Affecting Fringe Width

$$\beta \propto \frac{\lambda D}{d}$$β∝dλD​

Increases with:

• Wavelength
• Distance

Decreases with:

• Slit separation

---

8. Diffraction of Light

Diffraction is bending of light around obstacles.

Key Condition:

• Significant when slit width ≈ wavelength

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9. Single Slit Diffraction

Minima Condition:

$$a \sin\theta = n\lambda$$asinθ=nλ

Important Feature:

• Central maximum is widest and brightest

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10. Difference Between Interference & Diffraction

Feature	Interference	Diffraction
Source	Two sources	Single slit
Fringes	Equal width	Unequal
Intensity	Same	Decreasing

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11. Polarization of Light

Polarization restricts light vibrations to one plane.

Conclusion:

• Light is transverse wave

---

12. Polarizers

Devices that produce polarized light.

Effect:

• Reduce intensity

---

13. Brewster’s Law

$$\tan\theta_B = n$$tanθB​=n

At Brewster Angle:

• Reflected light is completely polarized

---

14. Intensity of Light

$$I \propto A^2$$I∝A2

Where:

• $A$A = amplitude

---

15. Path Difference and Phase Difference

$$\Delta \phi = \frac{2\pi}{\lambda} \times \text{path difference}$$Δϕ=λ2π​×path difference

Units:

• Phase → radians
• Path difference → meters

---

16. Diffraction Pattern Features

• Central maximum is brightest
• Width decreases with slit width
• Intensity decreases away from center

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17. Important NEET Formulas

• $\beta = \frac{\lambda D}{d}$β=dλD​
• $a\sin\theta = n\lambda$asinθ=nλ
• $I \propto A^2$I∝A2
• $\tan\theta_B = n$tanθB​=n

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18. Common Mistakes

❌ Confusing interference and diffraction
❌ Forgetting coherence condition
❌ Mixing constructive & destructive formulas
❌ Ignoring units

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19. Quick Revision Tips

• Remember fringe width formula
• Central maximum is widest
• Diffraction depends on slit size
• Polarization proves transverse nature

---

Conclusion

Wave Optics is a high-yield and conceptual chapter.

Focus on:

• Interference formulas
• Diffraction conditions
• Polarization concepts

👉 With proper understanding, you can easily score full marks in this chapter.