NEET UG Physics Practice Paper – Dual Nature & Atoms (Set 14)

Attempt all 30 MCQs and check your score instantly.

1. Photoelectric effect proves:

particle nature
wave nature
dual nature
none

2. Einstein photoelectric equation:

hf = KE + φ
V=IR
F=ma
none

3. Threshold frequency depends on:

material
intensity
wavelength
none

4. Kinetic energy depends on:

frequency
intensity
material
none

5. De Broglie wavelength:

h/p
p/h
hv
none

6. Wave nature of electron proved by:

Davisson-Germer
Rutherford
Bohr
none

7. Bohr radius ∝:

n²
n
1/n
none

8. Energy levels in atom:

discrete
continuous
random
none

9. Ionization energy:

remove electron
add electron
move electron
none

10. Spectral lines due to:

transitions
collisions
motion
none

11. Photon energy:

hf
h/v
hv²
none

12. Photon momentum:

h/λ
λ/h
hv
none

13. Work function is:

minimum energy
max energy
zero
none

14. Stopping potential depends on:

frequency
intensity
material
none

15. Mass-energy relation:

E=mc²
V=IR
F=ma
none

16. Electron charge:

-1.6×10⁻¹⁹ C
+1.6×10⁻¹⁹ C
0
none

17. Electron mass:

9.1×10⁻³¹ kg
10⁻²⁷
10⁻²³
none

18. Energy levels depend on:

n
mass
charge
none

19. Frequency of emitted photon:

ΔE/h
h/ΔE
none
zero

20. Hydrogen spectrum:

line spectrum
continuous
none
zero

21. Atomic model by Bohr:

quantized orbits
random
none
zero

22. Electron transition:

photon emission
absorption
none
zero

23. De Broglie applies to:

all particles
only electrons
only photons
none

24. Wave nature visible for:

small particles
large bodies
both
none

25. Photon has:

zero mass
mass
charge
none

26. Photon speed:

c
v
none
zero

27. Photoelectric current depends on:

intensity
frequency
material
none

28. KE max formula:

hf-φ
φ-hf
hf
none

29. Energy quantization means:

discrete
continuous
none
zero

30. Planck constant unit:

J·s
J
s
none

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NEET UG Physics Notes – Dual Nature of Matter & Radiation + Atoms (Set 14)

This combined revision chapter is extremely important for NEET UG, as it covers modern physics, which is one of the most scoring areas. Questions are generally direct, formula-based, and conceptual, making it easier to secure marks with proper clarity.

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1. Dual Nature of Radiation

Light shows dual nature:

• Wave nature → Interference, diffraction
• Particle nature → Photoelectric effect

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2. Photoelectric Effect

When light falls on a metal surface, electrons are emitted.

Key Observations:

• Emission is instantaneous
• Depends on frequency, not intensity
• Below threshold frequency → no emission

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3. Einstein’s Photoelectric Equation

$$hf = KE_{max} + \phi$$hf=KEmax​+ϕ

Where:

• $h$h = Planck’s constant
• $f$f = frequency
• $\phi$ϕ = work function

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4. Work Function (φ)

Minimum energy required to remove an electron.$$\phi = h f_0$$ϕ=hf0​

Depends on:

• Nature of material

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5. Stopping Potential

Stopping potential is the potential needed to stop the fastest electrons.$$eV_0 = KE_{max}$$eV0​=KEmax​

Important:

• Depends only on frequency, not intensity

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6. Effect of Intensity

• Intensity affects number of electrons (current)
• Does NOT affect kinetic energy

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7. Photon

Light consists of particles called photons.

Properties:

• Energy: $E = hf$E=hf
• Momentum: $p = h/\lambda$p=h/λ
• No rest mass
• Travels with speed $c$c

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8. De Broglie Hypothesis

All particles have wave nature.$$\lambda = \frac{h}{p}$$λ=ph​

Important Insight:

• Wave nature visible for microscopic particles

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9. Davisson-Germer Experiment

• Proved wave nature of electrons
• Confirmed de Broglie hypothesis

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10. Bohr’s Model of Atom

Postulates:

• Electrons move in fixed orbits
• Energy levels are quantized
• No radiation in stable orbits

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11. Radius of Orbit

$$r_n \propto n^2$$rn​∝n2

Meaning:

• Higher orbit → larger radius

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12. Energy of Electron

$$E_n = -\frac{13.6}{n^2} \, \text{eV}$$En​=−n213.6​eV

Key Insight:

• Energy is negative → bound system

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13. Spectral Lines

Produced due to electron transitions between energy levels.

Frequency:

$$\nu = \frac{\Delta E}{h}$$ν=hΔE​

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14. Hydrogen Spectrum

Hydrogen emits line spectrum.

Series:

• Lyman (UV)
• Balmer (visible)
• Paschen (IR)

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15. Ionization Energy

Energy required to remove electron from ground state.

For Hydrogen:

• 13.6 eV

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16. Energy Transitions

• Electron jumps to higher level → absorbs energy
• Electron falls → emits photon

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17. Mass-Energy Relation

$$E = mc^2$$E=mc2

Importance:

• Basis of nuclear energy

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18. Important NEET Formulas

• $hf = KE + \phi$hf=KE+ϕ
• $\lambda = h/p$λ=h/p
• $E = hf$E=hf
• $p = h/\lambda$p=h/λ
• $E_n = -13.6/n^2$En​=−13.6/n2
• $\nu = \Delta E/h$ν=ΔE/h

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19. Common Mistakes

❌ Thinking intensity affects kinetic energy
❌ Forgetting threshold frequency condition
❌ Mixing photon energy and electron energy
❌ Ignoring units (eV, J, etc.)

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20. Quick Revision Tips

• Photoelectric effect → particle nature
• Interference → wave nature
• De Broglie → dual nature
• Bohr model → quantized orbits

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Conclusion

Dual Nature and Atoms is a high-scoring and easy chapter in NEET.

Focus on:

• Photoelectric equations
• De Broglie relation
• Bohr model formulas
• Energy transitions

👉 With proper understanding, you can secure full marks from modern physics.