List of top Questions asked in Maharashtra Class XII

Distinguish between interference and diffraction of light. A double slit arrangement produces interference fringes for sodium light of wavelength 589 nm, that are 0.20 degree apart. What is the angular fringe separation if the entire arrangement is immersed in water? (R.I. of water = 1.33)
A galvanometer has a resistance of 50 \(\Omega\) and a current of 2 mA is needed for its full scale deflection. Calculate resistance required to convert it. (i) into an ammeter of 0.5 A range. (ii) into a voltmeter of 10 V range.
Diameter of a water drop is 0.6 mm. Calculate the pressure inside a liquid drop. (T = 72 dyne/cm, atmospheric pressure = \(1.013 \times 10^5\) N/m\(^2\))
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.
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.
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).
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.
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
Explain harmonics and overtones.
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.
Two coils having self inductances 60 mH each, are coupled with each other. If the coefficient of coupling is 0.75, calculate the mutual inductance between them.
What is the work done by an external uniform magnetic field perpendicular to the velocity of a moving charge?
What do you mean by a thermodynamic system?
Find kinetic energy of 1 litre of an ideal gas at S.T.P.
Which of the following equations gives correct expression for the internal resistance of a cell by using potentiometer?
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 --