Physics Model set 1 shaalaa.com 2021-2022 HSC Science (General) 12th Standard Board Exam Question Paper Solution

A stone is tied to one end of a string. Holding the other end, the string is whirled in a horizontal plane with progressively increasing speed. It breaks at some speed because ______ 

The gravitational forces of the earth are greater than the tension in the string 

The required centripetal force is greater than the tension sustained by the string

The required centripetal force is lesser than the tension in the string

The centripetal force is greater than the weight of the stone

The surface tension of a liquid at critical temperature is ______ 

Infinity

Zero

Same as any other temperature

Can not be determined

The integral multiple of fundamental frequencies are ______ 

beats

resonance

overtones

harmonics

Two S.H.M.’s have zero phase difference and equal amplitudes A. The resultant amplitude on their composition will be ______ 

2 A

zero

`sqrt2`A

`sqrt"2A"`

A strong magnetic field is applied to a stationary electron. Then the electron ______ 

moves in the direction of the field

remained stationary

moves perpendicular to the direction of the field

moves opposite to the direction of the field

In which of the following devices, the eddy current is not used ______ 

Electromagnet

Induction furnace

Electric heater

Magnetic breaking in train

The force between two parallel current-carrying conductors is F. If the current in each conductor is doubled, then the force between them becomes ______  

4F

2F

F

F/4

Calculate the value of λ_max for radiation from a body having a surface temperature of 3000 K. (b = 2.897 x 10-3 m K) 

9935 Å

9656 Å

9421 Å

9178 Å

Planck's constant is 6.6 × 10^-34 Js. The momentum of each photon is given radiation Is 3.3 × 10^-29 kg/s. The λ of radiation is ______.

2 × 10¹⁰ m 

2 × 10⁷ m 

2 × 10⁵ m 

2 × 10^-5 m 

In Hydrogen, the electron jumps from the fourth orbit to the second orbit. The wavenumber of the radiations emitted by an electron is ______  

`"R"/16`

`(3"R")/16`

`(5"R")/16`

`(7"R")/16`

State the equation for impedance Z in an A.C. circuit.

What is the relation between phase difference and Optical path in terms of speed of light in a vacuum?

What are linear isotropic dielectrics?

Are Kirchhoff’s laws applicable to both AC and DC circuits?

Above what temperature, all bodies radiate electromagnetic radiation? 

What is Solenoid?

The minimum frequency for photoelectric effect on metal is 7 × 10¹⁴ Hz, Find the work function of the metal. 

Two bodies have their moments of inertia I and 2I respectively about their axis of rotation. If their kinetic energies of rotation are equal, then what is the ratio of their angular velocity.

Define linear S.H.M.

What is polar dielectrics? 

What is nonpolar dielectric? 

State properties of an ideal fluid.

State any two advantages and disadvantages of a photodiode. 

Draw a neat labelled ray diagram of the Fresnel Biprism experiment showing the region of interference. 

State any two characteristics of a series LCR AC resonance circuit.

Four resistances 6Ω, 6Ω, 6Ω and 18Ω form a Wheatstone bridge. Find the resistance which connected across the 18Ω resistance will balance the network.

3 mole of a gas at temperature 400 K expands isothermally from an initial volume of 4 litres to a final volume of 8 litres. Find the work done by the gas. (R = 8.31 J mol^-1 K^-1)  

White light consists of wavelengths from 400 nm to 700 nm. What will be the wavelength range seen when white light is passed through a glass of refractive index 1.55?

A bucket containing water is tied to one end of a rope 5 m long and it is rotated in a vertical circle about the other end. Find the number of rotations per minute in order that the water in the bucket may not spill.

Starting with 𝑟 = `(ε_0h^2n^2)/(pimZe^2),` Show that the speed of an electron in n^th orbit varies inversely to principal quantum number. 

Find relation for Bohr magneton.

Show that for radioactive decay N(t) = `"N"_"O" "e"^{-λ"t"}`, where symbols have their usual meaning.

Draw the circuit diagram of a half-wave rectifier. Hence explain its working. 

Derive an expression for the kinetic energy of a rotating body with uniform angular velocity. 

What is the photoelectric effect? Define stopping potential and photoelectric work function. 

Derive an expression for the effective capacitance of three parallel plate capacitors connected in series.

How is potential gradient measured? Explain.

Two wires of the same material and same cross-section are stretched on a sonometer. One wire is loaded with 1 kg and another is loaded with 9 kg. The vibrating length of the first wire is 60 cm and its fundamental frequency of vibration is the same as that of the second wire. Calculate the vibrating length of the other wire. 

A Rectangular coil of 10 turns, each of area 0.05 m², is suspended freely in a uniform magnetic field of induction 0.01 T. A current of 30 µA is passed through it.

(i) What is the magnetic moment of the coil?

(ii) What is the maximum torque experienced by the coil?

A radio can tune over the frequency range of a portion of the MW broadcast band (800kHz -1200kHz). If its LC circuit has an effective inductance of 200mH, what must be the range of its variable condenser? 

The velocity of the three molecules is 2 km s^-1, 4 km s^-1, 6 km s^-1. Find (i) mean square velocity (ii) root mean square velocity. 

One gram of water (1 cm³) becomes 1671 cm³ of steam at a pressure of 1 atm. The latent heat of vaporization at this pressure is 2256 J/g. Calculate the external work and the increase in internal energy. 

Describe the construction and working of a transformer with a neat labelled diagram.

Derive Laplace’s law for spherical membrane of bubble due to surface tension.

Explain the thermodynamics of the isochoric process.  

1000 calories of radiant heat are incident on a body. If the body absorbs 400 calories of heat, find the coefficient of emission of the body. 

Explain constructive and destructive interference with the help of a diagram?

Waves produced by two vibrators in a medium have wavelength 2 m and 2.1 m respectively. When sounded together they produce 8 beats/second. Calculate wave velocity and frequencies of the vibrators.

Using Ampere's law, obtain an expression for the magnetic induction near a current-carrying straight infinitely long wire. 

An electron in an atom is revolving around the nucleus in a circular orbit of a radius of 5.3 x 10^-11 m, with a speed of 2 x 10⁶ m/s. Find the resultant orbital magnetic moment and angular momentum of the electron. [e = 1.6 x 10^-19 C, m_e= 9.1 x 10^-31 kg]