List of top Physics Questions

The kinetic energy of electron and photon arc the same. The relation between their De - Broglie wavelengths $ \lambda _e $ and $ \lambda _p $ is
A solid cylinder of mass $ M $ and radius $ R $ rolls on a flat surface. Find its moment of inertia about the line of contact.
An extrinsic semiconductor with electrons as majority carriers can be obtained by doping $ Ge $ or $ Si $ with
The difference between the maximum and minimum values of resistance of a resistor with the color scheme green-green-red-silver is
Which of the following is the indirect way of generating $ FM $ ?
A physical quantity X is given by $X=\frac{2k^{3}l^{2}}{m\sqrt{n}}$ The percentage error in the measurements of k, l, m and n are 1%, 2%, 3% and 4% respectively. The value of X is uncertain by
The magnetic field due to a current in a straight wire segment of length $L$ at a point on its perpendicular bisector at a distance $r (r >> L)$
A metal rod of length ????and cross-sectional area ????is heated through $???? \, {^{\circ}C}$. What is the force required to prevent the expansion of the rod lengthwise ? [Y = Young's modulus of the material of rod , $\alpha$ = coefficient of linear expansion]
A lift of mass $m$ is connected to a rope which is moving upward with maximum acceleration $a$. For maximum safe stress, the elastic limit of the rope, is $T$. The minimum diameter of the rope is (g = gravitational acceleration)
The resistance of a wire is ‘R’ ohm. If it is melted and stretched to ‘n’ times its original length, its new resistance will be
A rope is wound around a hollow cylinder of mass 3 kg and radius 40 cm. What is the angular acceleration of the cylinder if the rope is pulled with a force of 30 N?
A thin prism having refracting angle 10° is made of glass of refractive index 1.42. This prism is combined with another thin prism of glass of refractive index 1.7. This combination produces dispersion without deviation. The refracting angle of second prism should be
Preeti reached the metro station and found that the escalator was not working. She walked up the stationary escalator in time t1. On other days, if she remains stationary on the moving escalator, then the escalator takes her up in time t2. The time taken by her to walk up on the moving escalator will be
A spherical black body with a radius of 12 cm radiates 450 watt power at 500 K. If the radius were halved and the temperature doubled, the power radiated in watt would be
A long solenoid of diameter 0.1 m has 2 × 104 turns per meter. At the centre of the solenoid, a coil of 100 turns and radius 0.01 m is placed with its axis coinciding with the solenoid axis. The current in the solenoid reduces at a constant rate to 0 A from 4 A in 0.05 s. If the resistance of the coil is 10π2 Ω, the total charge flowing through the coil during this time is
In an electromagnetic wave in free space the root mean square value of the electric field is Erms = 6 V/m. The peak value of the magnetic field is
Two astronauts are floating in gravitational free space after having lost contact with their spaceship. The two will:
The bulk modulus of a spherical object is ‘B’. If it is subjected to uniform pressure ‘p’, the fractional decrease in radius is
If θ1 and θ2 be the apparent angles of dip observed in two vertical planes at right angles to each other, then the true angle of dip θ is given by
The ratio of resolving powers of an optical microscope for two wavelengths λ1 = 4000 Å and λ2 = 6000 Å is
Consider a drop of rain water having mass 1 g falling from a height of 1 km. It hits the ground with a speed of 50 m/s. Take g constant with a value 10 m/s2. The work done by the (i) gravitational force and the (ii) resistive force of air is
The given electrical network is equivalent to
The given electrical network is equivalent to
Which of the following statements are correct?
  1. Centre of mass of a body always coincides with the centre of gravity of the body.
  2. Centre of mass of a body is the point at which the total gravitational torque on the body is zero.
  3. A couple on a body produce both translational and rotational motion in a body.
  4. Mechanical advantage greater than one means that small effort can be used to lift a large load.
A spring of force constant k is cut into lengths of ratio 1 : 2 : 3. They are connected in series and the new force constant is k'. Then they are connected in parallel and force constant is k''. Then k' : k'' is
A Carnot engine having an efficiency of \(\frac {1}{10}\) as heat engine, is used as a refrigerator. If the work done on the system is 10 J, the amount of energy absorbed from the reservoir at lower temperature is