Maharashtra Board Class 12 Physics Important Questions 2027 (Repeated in Board Exams)

Obtain an expression for the maximum speed of a vehicle along horizontal circular curved road.

A ceiling fan has moment of inertia of 2 kg m². It attains maximum frequency of 60 r.p.m. in 2 seconds. Calculate its power rating.

The MI of ring of radius 'R' and mass 'M' about its central axis is _____ (a) 2 MR² (b) MR²/2 (c) MR² (d) (3/2) MR²

State and prove the law of conservation of angular momentum.

Define surface tension. Obtain the relation between surface tension and surface energy.

Calculate the radius of water drop, so that the excess pressure inside it is 24 N/m². [Surface tension of water = 7.2 x 10^-2 N/m]

When a number of droplets coalesce to form a single drop, the total surface area of the drop _____. (a) decreases (b) becomes zero (c) remains same (d) increases

Using Newton's law of viscosity for streamline flow, derive an expression for coefficient of viscosity.

Two capillary tubes of radii 0.3 cm and 0.6 cm are dipped in the same liquid, the ratio of heights to which the liquid will rise in the tubes is _____. (a) 1 : 2 (b) 2 : 1 (c) 1 : 4 (d) 4 : 1

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

The ratio of emissive power of a perfect black body at 927 deg C and 327 deg C is ____. (a) 2 : 1 (b) 4 : 1 (c) 8 : 1 (d) 16 : 1

For a thermodynamic system : Define : (a) Mechanical equilibrium (b) Chemical equilibrium

Define isothermal process. Obtain an expression for work done during isothermal process. Draw P-V diagram.

0.5 mole of an ideal gas at 300 K, expands isothermally from an initial volume of 2 L to a final volume of 6 L. Calculate : (a) work done by the gas (b) heat supplied to the gas [Given : R = 8.31 J mol^-1 K^-1]

Explain the cyclic process with the help of a neat p-V diagram.

What do you mean by a thermodynamic system?

The first law of thermodynamics is consistent with the law of conservation of _____. (a) momentum (b) energy (c) mass (d) velocity

Write the differential equation for linear S.H.M.

Distinguish between free and forced vibrations.

State differential equation of linear S.H.M. hence obtain an expression for acceleration, velocity and displacement of a particle performing S.H.M.

A body of mass 0.8 kg performs linear S.H.M. It experiences a restoring force of 0.4N, when its displacement from mean position is 4 cm. Determine Force constant and Period of S.H.M.

Define second's pendulum.

The velocity of bob of a second's pendulum when it is 6 cm from its mean position and amplitude of 10 cm, is _____. (a) 8 pi cm/s (b) 6 pi cm/s (c) 4 pi cm/s (d) 2 pi cm/s

Distinguish between harmonics and overtones. [Any Two points]

Two tuning forks having frequencies 160 Hz and 170 Hz are sounded together to produce sound waves. The velocity of sound in air is 326.4 m/s. Calculate the difference between wavelengths of these waves.

What is interference of light? State any four conditions for obtaining well defined and steady interference pattern.

A star is emitting light at the wavelength of 4000 Angstrom. Determine the limit of angular resolution of a telescope having an objective of diameter of 400 cm.

Using analytical method, obtain an expression for the fringe width of two interfering waves.

What is Brewster's law? Derive the formula for Brewster's angle.

The property of light which remains unchanged when it travels from one medium to another is _____. (a) velocity (b) wavelength (c) amplitude (d) frequency

Derive laws of reflection of light using Huygens' principle.

State the formula for electric field intensity due to uniformly charged spherical shell.

When n number of capacitors having each of capacity 'C' are connected in series, their equivalent capacity is (a) 1/C (b) nC (c) C/n (d) 1/(nC)

An electric dipole consists of two unlike charges of magnitude 2 x 10^-6 C each and separated by 4 cm. The dipole is placed in an external electric field of 10⁵ N/C. Calculate the work done by an external agent to turn the dipole through 180 deg.

What are polar molecules and non polar molecules?

A parallel plate capacitor filled with air has an area 6 cm² and the plate separation is 2 mm. Calculate its capacity.

Which of the following equations gives correct expression for the internal resistance of a cell by using potentiometer? (a) r = R(V/E - 1) (b) r = R(1 - E/V) (c) r = R(1 - V/E) (d) r = R(E/V - 1)

State the advantages of a potentiometer over a voltmeter.

A galvanometer has a resistance of 40 ohm and a current of 4 mA is needed for full scale deflection. What is the resistance and how is it to be connected to convert the galvanometer (a) into an ammeter of 0.4 A range and (b) into a voltmeter of 5 V range?

What is the resistance of an ideal voltmeter?

Derive an expression for the magnetic field produced by a current in a circular arc of a wire using Biot-Savart law.

Cyclotron can not accelerate _____ (a) protons (b) alpha-particles (c) neutrons (d) deuterons

Obtain an expression for magnetic induction of a toroid of N no. of turns about an axis passing through its centre and perpendicular to plane. [Second part:] A Carnot refrigerator operates between 150 K and 200 K, calculate its coefficient of performance.

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 x 10^-2 N/m.

State the formula for magnetic induction produced by a current in a circular arc of a wire. Hence find the magnetic induction at the centre of a current carrying circular loop.

Define magnetization. State its S.I. unit and dimensions. What is the relation between permeability and magnetic susceptibility?

Obtain an expression for period of a bar magnet vibrating in a uniform magnetic field and performing angular S.H.M.

Obtain an expression for orbital magnetic moment of an electron revolving around the nucleus of an atom.

Distinguish between diamagnetic and paramagnetic substances.

A bar magnet of moment of inertia of 500 g cm² oscillates with a time period of 3.142 seconds in a horizontal plane. What is its magnetic moment if the horizontal component of earth's magnetic field is 4 x 10^-5 T ?

Define : (i) Self inductance (ii) Mutual inductance. [Second part:] A conducting loop of area 1 m² is placed normal to a uniform magnetic field of 3 Wb/m². If the magnetic field is uniformly reduced to 1 Wb/m² in 0.5 second, calculate the induced e.m.f. produced in the coil.

A conducting rod of length l, rotates about one of its ends in a uniform magnetic field B, with a constant angular velocity omega. If the plane of rotation is perpendicular to B, the e.m.f. induced between the ends of rod is _____. (a) (1/2) B omega l² (b) B omega l² (c) 2 B omega l² (d) B omega l

With the help of neat diagram explain construction of a transformer. [Second part:] Calculate energy required to build up current of 1A in an inductor of inductance 20 mH.

What are Eddy currents? State its two applications.

An emf of 90 mV is induced in the winding of a coil, when current in a nearby coil is increasing at the rate of 4.5 A/s. What is the mutual inductance of the two coils?

An alternating voltage source given by e = 140 sin(314.2 t) is connected across a pure resistor of 50 ohm. Determine : (i) Frequency of the source. (ii) RMS value of emf.

Using phasor diagram for a series LCR circuit, obtain an expression for impedance. Define admittance.

In a purely inductive and capacitive circuit, power factor is, _____ (a) one (b) zero (c) infinity (d) 10

Obtain an expression for average power dissipated in a series LCR circuit.

Define the terms : (a) Inductive reactance (b) Capacitive reactance (c) Impedance

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

What is photoelectric effect? Describe with neat circuit diagram an experimental setup of photoelectric effect.

An electron, a proton, an alpha-particle and a hydrogen atom are moving with the same kinetic energy. The associated de-Broglie wavelength will be longest for - (a) proton (b) electron (c) hydrogen atom (d) alpha-particle

In a photoelectric experiment, the stopping potential is 1.5V. What is the maximum kinetic energy of a photoelectron?

Calculate the shortest wavelength of Paschen series and the longest wavelength of Balmer series for hydrogen atom.

State any two postulates of Bohr's theory of hydrogen atom.

An electron in hydrogen atom stays in its second orbit for 10^-8 s. How many revolutions will it make around the nucleus in that time? [Given : e = 1.6 x 10^-19 C, m = 9.1 x 10^-31 kg]

Derive an expression for radius of nth Bohr orbit.

Calculate the change in angular momentum of electron when it jumps from third orbit to first orbit in hydrogen atom.

The Boolean equation for NOR gate is (a) Y = A.B (b) Y = (A + B) bar (c) Y = A bar (d) Y = A + B

With a neat circuit diagram, explain the working of a full wave rectifier. Draw input-output waveforms.

Define logic gate and explain why NOT gate is called an inverter. [Second part:] The transistor is in the common emitter configuration. Its DC current gain is 50. If collector current is 3mA, calculate the base current.

With the help of a neat circuit diagram, explain the working of a half wave rectifier. Draw input and output waveforms.

An LED emits light when its ____ (a) junction is reverse biased. (b) depletion region widens. (c) holes and electrons recombine. (d) junction becomes hot.