Physics Model set 2 shaalaa.com 2021-2022 HSC Science (General) 12th Standard Board Exam Question Paper Solution

The average energy per molecule is proportional to ______ 

the pressure of the gas

the volume of the gas

the absolute temperature of the gas

the mass of the gas

Which of the following system freely allows the exchange of energy and matter with its environment? 

Closed

Isolated

Open

partially closed

Which of the following cannot produce two coherent sources?

Lloyd’s mirror

Fresnel biprism

Young’s double-slit

Prism

The role of inductance is equivalent to ______ 

inertia

force

energy

momentum

A particle is moving in a circle with uniform speed. Its motion is ______ 

Periodic and simple harmonic

Non-periodic

Periodic but not simple harmonic

Non-periodic but simple harmonic 

In the law of tension, the fundamental frequency of the vibrating string is, ______   

inversely proportional to the square root of tension

directly proportional to the square of tension

directly proportional to the square root of tension

inversely proportional to the density 

A dipole is placed in a uniform electric field, its potential energy will be minimum when the angle between its axis and field is ______ 

2π

π

`π/2`

Zero

Four resistances 4 Ω, 8Ω, XΩ and 12Ω are connected in a series to form Wheatstone’s network. If the network is balanced, the value of X is ______.

24

18

12

8

6

What is the magnetization of a bar magnet having a length of 6 cm and the area of cross-section 5 cm²?

1.2 × 10^-4 A/m 

3.3 × 10⁴ A/m 

1.25 × 10^-4 A/m 

3.3 × 10^-4 A/m

A coil of resistance 300Ω and inductance 1.0 H is connected across an alternating voltage of frequency `300/(2pi)` Hz, therefore phase difference between the voltage and current in the circuit is ______ 

180°

90°

45°

0°

What is the energy of an electron in a hydrogen atom for n = ∞?  

During ice ballet, while in the outer rounds, why do the dancers outstretch their arms and legs.

What are cohesive forces?

On what, the values of absorption coefficient, reflection coefficient, and transmission coefficient depend, in addition to the material of the object on which the radiation is an incident? 

What is a thermodynamic process?

What does the phase of π/2 indicate in linear S.H.M.? 

The electron in the hydrogen atom is moving with a speed of 2.5 × 10⁶ m/s in an orbit of a radius of 0.5 Å. What is the Magnetic moment of the revolving electron?    

If the peak value of an alternating emf is 15V, what is its mean value over half cycle?

Draw a neat labelled diagram of a schematic of the experimental setup for the photoelectric effect. 

Derive the expression for magnetic field produced by a current in a circular arc of wire.

Differentiate between the reversible and irreversible processes.

Why and where are eddy currents are undesirable? How are they minimized? 

What are stationary waves? Why are they called stationary waves? 

Draw a neat labelled circuit diagram for transistors as common emitter amplifiers. 

Define surface tension 

A metal cube of length 4 cm radiates heat at the rate of 10 J/s. Find its emissive power at a given temperature. 

The magnetic flux through a loop varies according to the relation Φ = 8t² + 6t + 2, Φ is in milliweber and t is in second. What is the magnitude of the induced emf in the loop at t = 2 seconds?  

A solenoid of length π m and 5 cm in diameter has a winding of 1000 turns and carries a current of 5 A. Calculate the magnetic field at its centre along the radius.

Find the current in a circuit consisting of a coil and a capacitor in series with an A.C source of 110V (r.m.s.), 60Hz. The inductance of a coil is 0.80 H and its resistance is 50Ω. The capacitance of a capacitor is 8µF. 

The moment of inertia of a body about a given axis is 1.2 kgm². initially, the body is at rest. For what duration on the angular acceleration of 25 radian/sec² must be applied about that axis in order to produce rotational kinetic energy of 1500 joule?  

Explain the construction and working of Ferry’s black body.

Explain experimental setup for Fraunhofer diffraction with neat diagram. 

Show that even as well as odd harmonics are present as an overtone in modes of vibration of the string. 

Obtain an expression for the energy stored in a charged condenser. Express it in different forms. 

Draw the circuit symbol for NPN and PNP transistors. What is the difference in the Emitter, Base, and Collector regions of a transistor? 

Define angular S.H.M. and obtain its differential equation.

Explain graphically (i) positive work with varying pressure, (ii) negative work with varying pressure, and (iii) positive work at constant pressure. 

A magnet of magnetic moment 3Am² weighs 75 g. The density of the material of the magnet is 7500 kg/m³. what is magnetization? 

In Fraunhoffer diffraction by a narrow slit, a screen is placed at a distance of 2 m from the lens to obtain the diffraction pattern. If the slit width is 0.2 mm and the first minimum is 5 mm on either side of the central maximum, find the wavelength of light.

The work function of a surface is 3.1 eV. A photon of frequency 1 × 10¹⁵ Hz. Is an incident on it. Calculate the incident wavelength is photoelectric emission occurs or not.   

Using the expression for the energy of an electron in the n^th orbit, Show that `1/lambda = "R"_"H"(1/"n"^2 - 1/"m"^2),` Where symbols have their usual meaning. 

A cell of e.m.f 1.5V and negligible internal resistance is connected in series with a potential meter of length 10 m and the total resistance of 20 Ω. What resistance should be introduced in the resistance box such that the potential drop across the potentiometer is one microvolt per cm of the wire?  

Obtain an expression for maximum safety speed with which a vehicle can be safely driven along a curved banked road. 

Derive the relation between surface tension and surface energy per unit area.

Find an expression for the power expended in pulling a conducting loop out of a magnetic field.

Two capacitors each of capacity 2 μF are connected in parallel. This system is connected in series with the third capacitor of 12μF capacity. Find the equivalent capacity of the system.  

Derive an expression for axial magnetic field produced by current in a circular loop.

The maximum safe voltage that can be measured using a galvanometer of resistance G is V_m . Find the resistance to be connected in series with the galvanometer so that it becomes a voltmeter of range nV_m. 

Obtain the expression for the applied emf and the effective resistance of the circuit when alternating emf is applied to an LR circuit.

Calculate the longest wavelength in the Paschen series.

(Given R_H =1.097 ×10⁷ m^-1)