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Physics 12 Past Paper 2025 | Notely

HomePast papersPhysics 122025

All Physics 12 papers

Class 12 · Past paper

Physics 12 past paper 2025

50 published questions in this index. The full practice view lets you work through them and track your own attempts.

15 MCQs35 written questionsPractise this paper

Question index

16
Coulomb force between two electric charges is $120\text{ N}$. If the distance between the charges is doubled, the coulomb force will be:
MCQ1 marksannualElectric Potential And Capacitor
6
The resulting nucleus in given reaction is: $^1_0n + ^{137}_{56}Ba \rightarrow \underline{\quad\quad} + \gamma$
MCQ1 marksannualNuclear Physics
1
Which of the following **CANNOT** be accelerated using electric field?
MCQ1 marksannual
1
By **Coulomb's law**, prove that the force between two point charges is reduced in a medium other than free space.

This is a skimmable index, not a replacement for the study surface. Open the practice view to answer questions and use the linked study material.

Part B3 marksannual

1

Explain the concept of **Black body radiation** with the help of examples. Describe how energy is distributed over the wavelength range for different values of source temperature.…

Part C7 marksannual

2

According to Quantum theory, increasing the brightness of a beam of light without changing the color will increase:

MCQ1 marksannual

2

Briefly illustrate the variation of binding energy per nucleon with the mass number. Also draw the graph.

Part B3 marksannual

2

What is an AC generator? How is an AC generator used to produce an alternating current? Explain with the help of a graph between instantaneous emf and time.

Part C7 marksannual

3

Primary function of transformer is to change:

MCQ1 marksannual

3

Write three postulates of Bohr's atomic model.

Part B3 marksannual

3

Construct **phasor diagrams** and **impedance diagrams** of an R-L-C series circuit. Determine formula for impedance, phase angle and power factor.

Part C7 marksannual

4

A forward biased PN Junction offers:

MCQ1 marksannual

4

Differentiate 'statically induced emf' and 'dynamically induced emf'. Illustrate your answer with example.

Part B3 marksannual

4

What is a mass spectrograph? Explain its working. Also show that the radius of the circular path of an isotope depends upon its mass.

Part C7 marksannual

5

Which is **NOT** the characteristic of LASER?

MCQ1 marksannual

5

Write three sources of emf by clearly specifying the energy conversion in each.

Part B3 marksannual

5

Demonstrate **charging and discharging** of a capacitor through a resistance. Elaborate your answer with the help of Q-t graphs.

Part C6 marksannual

6

If an electron and a proton have the same de-Broglie wavelength, which particle has greater speed? Justify.

Part B3 marksannual

6

What are **X-rays**? How inner shell transitions in heavy elements result into emission of characteristic X-rays? Explain and draw diagrams.

Part C6 marksannual

7

Compton effect proves the:

MCQ1 marksannual

7

When is **Compton shift** maximum? Prove it.

Part B3 marksannual

7

State **Ampere's law**. Apply it to obtain a quantitative expression for the magnetic field inside a solenoid.

Part C6 marksannual

8

Which is an application of Mutual Induction?

MCQ1 marksannual

8

What is **rectification**? Describe the use of diodes for half and full wave rectification with circuit diagrams.

Part C6 marksannual

9

The temperature at which a ferromagnetic material becomes paramagnetic is called:

MCQ1 marksannual

9

How can a galvanometer be converted into an ammeter? Draw diagram as well.

Part B3 marksannual

10

SI unit of capacitive reactance is:

MCQ1 marksannual

10

A 300 kg load produces an extension 0.2 cm in a steel wire having length 2.0 m and cross-sectional area 15 cm². Determine: a) Stress, b) Strain, c) Young's Modulus for Steel (Y).

Part B3 marksannual

11

What are the causes of power losses in a transformer? Write any three.

Part B3 marksannual

12

Due to electric polarization of dielectric, the charge storing capacity of capacitor:

MCQ1 marksannual

12

A pure inductor is connected across a 10 V, 200 Hz AC supply and the current flowing through it is measured as 0.4 A. Determine the value of its inductance.

Part B3 marksannual

13

What is meant by **magnetic flux**? State its unit.

Part B3 marksannual

14

Which of the following series lies in the ultraviolet region?

MCQ1 marksannual

14

In which combination of capacitors the **energy stored** is maximum, parallel or series? Justify.

Part B3 marksannual

15

Which one belongs to **Hadrons**?

MCQ1 marksannual

15

Calculate the longest and the shortest wavelengths for the Paschen series.

Part B3 marksannual

16

Calculate the current through a single loop circuit if $\varepsilon = 120\text{ V}$, $R = 1000\text{ }\Omega$ and internal resistance $r = 0.01\text{ }\Omega$.

Part B3 marksannual

17

A particle having the mass of an electron and charge of proton is called:

MCQ1 marksannual

17

Briefly describe the working of a rheostat as a potential divider circuit with diagram.

Part B3 marksannual

18

Briefly describe the operation of an NPN transistor.

Part B3 marksannual

19

Why is the **emitter-base junction** forward biased and the **collector-base junction** reverse biased?

Part B3 marksannual

20

Distinguish between **emf** and **potential difference**. (Any three points)

Part B3 marksannual

21

Briefly explain the role of **moderators** and **control rods** in nuclear reactor.

Part B3 marksannual

22

What is **Coercivity**? Why is the coercive force of tungsten steel greater than that of iron?

Part B3 marksannual

23

Briefly explain the **magnetic force** acting on a stationary charged particle placed in a uniform magnetic field.

Part B3 marksannual

24

What are **superconductors**? Write down their four applications.

Part B3 marksannual

25

In an **RL series circuit**, will the current lag or lead the voltage? Illustrate your answer by drawing waveforms and phasor diagrams.

Part B3 marksannual

26

What is a Geiger-Müller counter? Briefly describe its working.

Part B3 marksannual

27

Deduce the expression for maximum output power delivered to a load resistance.

Part B3 marksannual

28

Write any three factors affecting the magnitude of the induced emf.

Part B3 marksannual