Sub. code 1021
NEB — GRADE XII
2083
Old Question
Physics Question Paper 2083 (Old Question)
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 old question question paper is for Class 12 Physics, 2083 (subject code 1021), carrying full marks of 75 with a pass mark of 32, to be completed within 3 Hours. Answers with step-by-step solutions are available for every question below.
Group A
Multiple Choice Questions
What is factor affecting radius of gyration of a body?
Angular speed
Axis of rotation
Angular acceleration
Acceleration due to gravity
The length of a pendulum is increased by 1%. By what percentage of the period of the motion increases?
9.8%
10%
11%
21%
A cork rises from the bottom of the water and finally floats in water. Its graphical representation will be:
If efficiency of petrol engine is η₁, and that of diesel engine is η₂, then, which of the following expression is correct?
In which of the following thermodynamic process of the gas, workdone is minimum?
Isothermal
Adiabatic
Isobaric
Isochoric
What is the distance between node and antinode in a stationary wave in terms of wavelength?
λ/2
λ/4
λ
2λ
Time taken by light to cross a glass slab of thickness 5 cm and refractive index of 1.5 will be:
0.2 ns
0.25 ns
0.3 ns
0.35 ns
Which of the following represents the process of production of emf by maintaining a difference of temperature between the two junctions of a loop of two dissimilar metals?
Seebeck effect
Joule effect
Peltier effect
Thomson effect
Which portion of the given figure represents the coercivity?
CD
AD
AG
AE
A coil has a resistance of 8Ω and an inductive reactance 6Ω. What will be the impedance?
6Ω
8Ω
10Ω
14Ω
A diode as a rectifier converts
Varying dc into constant dc
dc into ac
High voltage into low voltage
ac into dc
Group B
Short answer questions
The angular velocity of the earth around the sun increases when it comes closer to the sun, why?
A disc having moment of inertia 10 kg m² about its center rotates steadily with angular velocity of 20 rad s⁻¹. Find:
i) Rotational kinetic energy
ii) Number of revolution per second
State Stoke's law and use it to derive an expression for the determination coefficient of viscosity of given liquid.
Write equation of continuity. Also write its two applications.
Define simple harmonic motion. Write general equations for displacement and acceleration in simple harmonic motion.
Plot a graph of velocity of a particle in SHM.
What will be the time period of simple pendulum at the centre of the earth? Justify.
Apply first law of thermodynamics to obtain the relation Cₚ − Cᵥ = R, where symbols have their usual meanings.
A petrol engine consumes 10 kg of petrol in one hour. The calorific value of petrol is 1.14 × 10⁴ cal g⁻¹. The power of the engine is 30 kW. Calculate the efficiency of the engine.
Obtain Laplace's formula for velocity of sound in air starting from Newton's formula
A car producing note of frequency 500 Hz approaches and passes a stationary observer at the steady speed of 20 m s⁻¹. Calculate change of frequency heard by the observer.
(Velocity of sound = 340 m s⁻¹)
Analyze the given graph and name the type of material represented by graph A and graph B
Define potential gradient. A potentiometer wire is 10 m long. It has a resistance of 2 Ω. It is connected in series with a battery of 3 V and a resistance of 10 Ω. Calculate the potential gradient along the wire.
State and explain Lenz's law.
A bar magnet falls through a metal ring, will its acceleration be equal to g? Justify your answer.
According to Faraday's law of electromagnetic induction, induced emf
ε = −N dΦ/dt. What does the negative sign indicate?
Define rms value of current.
The emf in an ac circuit is represented as E = E₀ sin ωt. Show that voltage through an inductor leads current by π/2. Also draw a phasor diagram.
Why does a capacitor block d.c.?
Define half and mean life.
Calculate the value of half life and decay constant from Fig. (a).
Which one curve in Fig. (b) has more value of decay constant? Justify.
Draw free body diagram of oil drop falling through air in Millikan's oil drop experiment for both cases, when field is given and when field is absent. What is the conclusion of this experiment?
How do P and S waves differ?
Group C
Long Answer Questions
Thin films such as soap bubbles show beautiful colors when illuminated by white light. Why?
"The bright and dark fringes are equally spaced." Justify this statement from Young's double slits experiment.
A diffraction grating has 400 lines per mm and is illuminated normally by monochromatic light of wavelength 600 nm. Calculate:4
i) The grating spacing.
ii) The angle to the normal at which the first order maximum is seen.
iii) The number of diffraction maxima obtained.
Why is an end correction necessary for organ pipes?
How is it possible to estimate that the vessel kept under an open tap of water is about to fill? Justify.
In case of an organ pipe, notes of frequencies 200 Hz, 600 Hz and 1000 Hz are heard. Is the pipe open or closed?
Describe the various modes of vibration of the air column in a closed organ pipe.
What are excitation potential and ionization potential?
Given figure shows the different energy levels of a hydrogen atom. Estimate the energy values for n = 4 and 5. How many different transitions are possible?
What is rectifier? Describe the working of full wave rectifier using two P-N junction diodes.
What is photo electric effect?
Describe Einstein's photoelectric equation.
State and explain Bragg's law of X-ray diffraction.
Calculate the value of Planck's constant and work function from the given figure.
A circular coil of radius R is carrying a constant current I. Find an expression for magnetic field at point P, which is at a distance x on its axial line.
Why is Hall voltage much more measurable in semiconductors than metals? Explain
Draw magnetic field lines around the two parallel current carrying conductors in which currents are in opposite direction.
Two long parallel conductors are placed 0.1 m apart and carry currents of 3 A and 2 A, respectively, in the same direction. Calculate the force per unit length experienced by each conductor due to the other.
(μ₀ = 4π × 10⁻⁷ Hm⁻¹)