Physics Official 2022-2023 HSC Science (General) 12th Standard Board Exam Question Paper Solution

Choose the correct option.

The mean free path λ of molecules is given by where n is the number of molecules per unit volume and d is the diameter of the molecules. 

`sqrt(2/(pind^2))`

`1/(pind^2)`

`1/(sqrt2pind^2)`

`1/sqrt(2pind^2)`

`sqrt(2/(pind))`

`1/(2pind^2)`

`1/sqrt(2pind)`

The first law of thermodynamics is concerned with the conservation of ______.

momentum

energy

temperature

mass

velocity

Y = `overline("A" + "B")` is the Boolean expression for ______.

OR - gate

AND - gate

NOR - gate

NAND - gate

Which property of light does not change when it travels from one medium to another?

Velocity

Wavelength

Amplitude

Frequency

A circular coil of 100 turns with a cross-sectional area of 1 m² is kept with its plane perpendicular to the magnetic field of 1 T. The magnetic flux linkage is ______.

1 Wb

50 Wb

100 Wb

200 Wb

If ‘θ’ represents the angle of contact made by a liquid which completely wets the surface of the container then ______.

θ = 0

0 < θ < `pi/2`

θ = `pi/2`

`pi/2` < θ < π

An LED emits visible light when it's ______.

Junction is reverse biased.

Depletion region widens.

Holes and electrons recombine.

The junction becomes hot.

Choose the correct option:

Soft iron is used to make the core of the transformer because of its ______.

Low coercivity and low retentivity

Low coercivity and high retentivity

High coercivity and high retentivity

High coercivity and low retentivity

If the maximum kinetic energy of emitted electrons in the photoelectric effect is 2eV, the stopping potential will be ______.

0.5 V

1.0 V

1.5 V

2.0 V

Choose the correct option.

The radius of the 4^th orbit of the electron will be smaller than its 8^th orbit by a factor of ______.

2

4

8

16

What is the value of resistance for an ideal voltmeter?

What is the value of force on a closed circuit in a magnetic field?

What is the average value of alternating current over a complete cycle?

An electron is accelerated through a potential difference of 100 volts. Calculate de-Broglie wavelength in nm.

If friction is made zero for a road, can a vehicle move safely on this road?

State the formula giving the relation between electric field intensity and potential gradient.

Calculate the velocity of a particle performing S.H.M. after 1 second, if its displacement is given by x = `5sin((pit)/3)`m.

Write the mathematical formula for Bohr magneton for an electron revolving in n^th orbit.

Define the coefficient of viscosity.

State the formula and S.I. units of coefficient of viscosity.

Obtain an expression for magnetic induction of a toroid of ‘N’ turns about an axis passing through its centre and perpendicular to its plane.

State and prove: Law of conservation of angular momentum.

Obtain an expression for the equivalent capacitance of two capacitors C₁ and C₂ connected in series.

Explain why the inductance of two coils connected in parallel is less than the inductance of either coil.

State how a moving coil galvanometer can be converted into an ammeter.

A 100 Ω resistor is connected to a 220 V, 50 Hz ac supply.

1. What is the rms value of current in the circuit?
2. What is the net power consumed over a full cycle?

A bar magnet of mass 120 g in the form of a rectangular parallelepiped, has dimensions l = 40 mm, b = 10 mm and h = 80 mm, with its dimension ‘h’ vertical, the magnet performs angular oscillations in the plane of the magnetic field with period π seconds. If the magnetic moment is 3.4 Am², determine the influencing magnetic field.

Differentiate between free and forced vibrations.

Compare the rate of loss of heat from a metal sphere at 827°C with the rate of loss of heat from the same at 427°C, if the temperature of the surrounding is 27°C.

An ideal monoatomic gas is adiabatically compressed so that its final temperature is twice its initial temperature. What is the ratio of the final pressure to its initial pressure?

The disintegration rate of a radio-active sample is 10¹⁰ per hour at 20 hours from the start. It reduces to 5 × 10⁹ per hour after 30 hours. Calculate the decay constant.

Derive the laws of reflection of light using Huygens’ principle.

Answer in brief.

State the postulates of Bohr’s atomic model.

Define Magnetization.

State formula and S.I. unit of Magnetization.

What is magnetic susceptibility?

State unit and dimensions of Magnetic susceptibility.

With the help of a circuit diagram describe the experiment to study the characteristics of the photoelectric effect. Hence discuss any 2 characteristics of the photoelectric effect.  

Describe with the help of a neat circuit diagram how you will determine the internal resistance of a cell by using a potentiometer. Derive the necessary formula.

Explain the working of the n-p-n transistor in a common base configuration.

Answer in brief.

Using differential equations of linear S.H.M, obtain the expression for (a) velocity in S.H.M., (b) acceleration in S.H.M.

Two tuning forks of frequencies 320 Hz and 340 Hz are sounded together to produce a sound wave. The velocity of sound in air is 326.4 m/s. Calculate the difference in wavelengths of these waves.

In a biprism experiment, the fringes are observed in the focal plane of the eyepiece at a distance of 1.2 m from the slits. The distance between the central bright and the 20th bright band is 0.4 cm. When a convex lens is placed between the biprism and the eyepiece, 90 cm from the eyepiece, the distance between the two virtual magnified images is found to be 0.9 cm. Determine the wavelength of light used.

Calculate the current flowing through two long parallel wires carrying equal currents and separated by a distance of 1.35 cm experiencing a force per unit length of 4.76 × 10^-2 N/m.

An alternative voltage given by V = 140 sin 314t is connected across a pure resistor of 50 Ω. Find

1. The frequency of the source.
2. The rms current is through the resistor.

An electric dipole consists of two opposite charges each of magnitude 1 μC, separated by 2 cm. The dipole is placed in an external electric field of 10⁵ N/C. Calculate the:

1. maximum torque experienced by the dipole and
2. work done by the external field to turn the dipole through 180°.

Derive an expression for the pressure exerted by a gas on the basis of the kinetic theory of gases.

Derive an expression for energy stored in the magnetic field in terms of induced current.

A wire 5 m long is supported horizontally at a height of 15 m along an east-west direction. When it is about to hit the ground, calculate the average e.m.f. induced in it. (g = 10 m/s²)

Derive an expression for the work done during an isothermal process.

104 J of work is done on a certain volume of a gas. If the gas releases 125 kJ of heat, calculate the change in internal energy of the gas.

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

Calculate the work done in blowing a soap bubble to a radius of 1 cm. The surface tension of soap solution is 2.5 × 10^-2 N/m.

Derive expressions for the linear velocity at the lowest position, mid-way position and top-most position for a particle revolving in a vertical circle, if it has to just complete circular motion without string slackening at the top.