Sub. code 1021
NEB — GRADE XII
2082
Model Question
Class 12 Physics Model Question 2082
The candidates are required to give their answers in their own words as far as practicable. The figures in the margin indicate full marks.
Pass Marks : 32
सबै प्रश्नको उत्तर दिनुहोस् । (Attempt All Questions)
This model question paper is for Class 12 Physics, 2082 (subject code 1021), carrying full marks of 75 with a pass mark of 32, to be completed within 3 Hours. Model answers are available for questions that have one — reveal them with a free account (a few reveals) or a paid plan (unlimited).
Group A
Rewrite the correct answer in your answer sheet
The torque due to the gravitational force on a body about its centre of mass is:
finite
infinite
zero
not measurable
For a simple pendulum, the graph between l and T² comes out to be:
straight line
parabola
hyperbola
circular
A liquid neither rises nor falls in a capillary tube. The angle of contact is:
0°
Less than 90
90°
Greater than 90°
A gas undergoes a cyclic process ABCDA as shown in figure. The part ABC of process is semicircular. The work done by the gas is:
400π J
1200π J
2456 J
200π J
A positive amount of thermal energy Q is transferred to an ideal gas from its surroundings. The internal energy of the gas increases and the gas does a positive amount of work W on its surroundings. The change of state of the gas is:
Isochoric
Isobaric
Isothermal
Adiabatic
The fundamental frequency for a particular organ pipe is 330 Hz. The pipe is closed at one end but open at the other. What is the frequency of its second mode?
110 Hz
165 Hz
660 Hz
990 Hz
If refractive index of a glass is 1.5, what will be its polarizing angle?
65.3°
56.3°
45°
42.3°
For a thermocouple, the inversion temperature is 600°C and the neutral temperature is 320°C. Find the temperature of the cold junction
40°C
20°C
80°C
60°C
An AC generator produces a voltage of peak value V. The frequency of rotation of the coil of the generator is f. The rms value of the voltage produced is
V / 2√2
V / √2
V√2
2V√2
An oil drop carrying a charge q has a mass m kg. It is falling freely in air with terminal velocity v, the electric field required to make the drop move upward with the same speed is
mg / q
2mg / q
mgv / q²
2mgv / q
The region of initiation of seismic energy within earth is called
Epicenter
Hypocenter
Pole
Optic center
Group B
Short answer question
Define moment of inertia.
State and explain the principle of conservation of angular momentum.
What is the power output of an electric motor turning at 4800 rpm and developing a torque of 4.30 Nm?
Define simple harmonic motion.
Draw a graph to show the variation of velocity with time of a particle in simple harmonic motion which is at mean position at t = 0.
A particle in simple harmonic motion has velocity of 8 cm/s at 12 cm from mean position and 12 cm/s at 8 cm from mean position. Find maximum velocity and maximum acceleration of the particle.
Why does water form a concave meniscus but mercury forms convex meniscus inside a capillary tube of glass?
How does viscosity of air change with temperature? Justify.
Calculate the rate of flow of glycerine of density 1.25 × 10³ kg/m³ through the conical section of a pipe, if the radii of its ends are 0.1 m and 0.04 m and the pressure drop across its length is 10 N/m².
State the first law of thermodynamics and use it to explain why cooling effect is observed on adiabatic expansion?
In the given figure, a Carnot engine drives a Carnot refrigerator. Determine Q₂, Q₃ and Q₄.
Obtain balanced condition of Wheatstone bridge circuit using Kirchhoff’s laws.
A potentiometer wire is 4 m long. It has a resistance of 10 Ω. It is connected in series with a battery of 2 V and resistance of 5 Ω. Calculate the potential gradient along the wire.
State Biot–Savart law. Derive an expression for magnetic field due to a long straight conductor using Ampere’s circuital law.
A current of 2 A enters at the corner ‘a’ of a square frame of wire of side 20 cm and leaves at opposite corner ‘c’. A magnetic field of B = 0.25 T acts in a direction perpendicular to the plane of the paper. Find the magnitude and direction of the magnetic forces on the four sides of the frame.
Two organ pipes are used to create a musical piece. An open pipe produces its first harmonic, while a closed pipe produces its first overtone. Both pipes produce the same note. What is the relationship between the lengths of the two pipes?
Define end correction
Describe different modes of vibration in a stretched string.
What property of a p–n junction diode enables its use in rectifiers?
Explain the construction and working of a full wave rectifier.
Write the truth table of two inputs NAND gate.
Define one curie.
Obtain a relation between half life and decay constant.
The half-life of a radioactive isotope is 10 days. What is the percentage of the sample remaining after 25 days?
Why and how did Laplace correct Newton's formula for velocity of sound in air?
What is the displacement amplitude for a sound wave having a frequency of 100 Hz and a pressure amplitude of 10 Pa? (Speed of sound in air is 340 m/s and density of air is 1.29 kg/m³)
Group C
long answer question
Why sound waves cannot be plane polarized?
On the basis of Young's double slit experiment, show that dark and bright fringes are equally spaced in interference.
The critical angle of water is 48°. What is its polarizing angle?
Diffraction grating is better than Young's double slit for measuring the wavelength of a monochromatic light. Explain.
In the given figure, an inductor of inductance L, a capacitor of capacitance C, a resistor of resistance R are connected in series and the combination is then connected to an alternating source of emf.
Draw a phase diagram for the circuit.
Calculate impedance of the circuit.
If L = 0.5 H and C = 20 μF, find the resonant frequency of the circuit.
Give an application of resonating a.c. circuit.
Why is 220 V a.c. more dangerous than 220 V d.c.? Explain.
What is natural radioactivity?
Obtain decay equation, N = N₀e⁻ˡᵗ, where symbols have their usual meanings.
What do you mean by current sensitivity and voltage sensitivity?
The half life of radon is 3.8 days. Calculate how much radon will be left out of 1024 milligram after 38 days
Paper Overview & Analysis
2082
Year
Model Question
Type
75
Full Marks
32
Pass Marks
3 Hours
Duration
50
Question Items
Question Type Breakdown
Group Breakdown
Chapter Breakdown
| First law of thermodynamics | 3 items | 4 marks |
| Radioactivity and Nuclear Reaction | 3 items | 7 marks |
| Polarization | 2 items | 3 marks |
| Rotational Dynamics | 1 item | 1 mark |
| Periodic motion | 1 item | 1 mark |
| Fluid statics | 1 item | 1 mark |
| Waves in pipes and strings | 1 item | 1 mark |
| Thermoelectric Effects | 1 item | 1 mark |
| Alternating Currents | 1 item | — |
| Electrons | 1 item | 1 mark |
| Wave motion | 1 item | — |
| Second law of thermodynamics | 1 item | 3 marks |
| Acoustic phenomena | 1 item | 1 mark |
| Interference | 1 item | 3 marks |
| Diffraction | 1 item | 2 marks |
| Electrical Circuits | 1 item | 1 mark |
Chapter breakdown covers 21 of 50 question items on this paper — the rest aren't tagged to a chapter yet.