List of top Questions asked in Maharashtra Board Class XII Exam

A solenoid of length \(\pi\) m and 5 cm in diameter has a winding of 1000 turns and carries a current of 5A. Calculate the magnetic field at its centre along the axis.
Obtain an expression for average power dissipated in a series LCR circuit.
State Einstein's photoelectric equation and mention physical significance of each term involved in it. The wavelength of incident light is 4000Å. Calculate the energy of incident photon.
State any four uses of Van de Graaff generator. In a parallel plate air capacitor, intensity of electric field is changing at the rate of \(2 \times 10^{11}\) V/ms. If area of each plate is 20 cm\(^2\), calculate the displacement current.
Derive an expression for law of radioactive decay. Define one becquerel (Bq).
In a thermodynamic system, define -- (a) Mechanical equilibrium (b) Chemical equilibrium and (c) Thermal equilibrium
Derive an expression for law of radioactive decay. Define one becquerel (Bq).
State and prove Kirchhoff's law of heat radiation.
Obtain an expression for practical determination of end correction -- (i) for a pipe open at both ends and (ii) for a pipe closed at one end.
A conducting bar is rotating with constant angular speed around a pivot at one end in a uniform magnetic field perpendicular to its plane of rotation. Obtain an expression for the rotational e.m.f. induced between the ends of the bar.
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 : \(e = 1.6 \times 10^{-19}\) C, \(m = 9.1 \times 10^{-31}\) kg ]
A flywheel of a motor has mass 100 kg and radius 1.5 m. The motor develops a constant torque of 2000 Nm. The flywheel starts from rest. Calculate the work done during the first 4 revolutions.
In a series LCR circuit, if resistance, inductive reactance and capacitive reactance are 3\(\Omega\), 8\(\Omega\) and 4\(\Omega\) respectively, calculate phase difference between voltage and current.
State the advantages of a potentiometer over a voltmeter.
Draw a neat and labelled circuit diagram for a full wave rectifier.
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.
A gas of 0.5 mole at 300 K expands isothermally from an initial volume of 2.0 litre to a final volume of 6.0 litre. What is the work done by gas?
Obtain an expression for the period of a bar magnet vibrating in a uniform magnetic field, performing S.H.M.
In a thermodynamic system, define -- (a) Mechanical equilibrium (b) Chemical equilibrium and (c) Thermal equilibrium
What is Brewster's law? Derive the formula for Brewster's angle.
Explain harmonics and overtones.
Using Newton's law of viscosity for streamline flow, derive an expression for coefficient of viscosity.
State and prove the law of conservation of angular momentum.
State any four advantages of light emitting diode (LED).
Calculate the energy radiated in one minute by a perfectly black body of surface area 200 cm\(^2\) when it is maintained at 127\(^{\circ}\)C.