List of top Physics Questions

If the earth has a mass nine times and radius four times that of planet X, the ratio of the maximum speed required by a rocket to pull out of the gravitational force of planet X to that of the earth is:
In the normal adjustment of an astronomical telescope, the objective and eyepiece are 32 cm apart. If the magnifying power of the telescope is 7, find the focal lengths of the objective and eyepiece.
Select the unit of the coefficient of mutual induction from the following.
A cell of emf E and internal resistance r is connected to two external resistances R1 and R2 and a perfect ammeter. The current in the circuit is measured in four different situations:
A 500 W heating unit is designed to operate on a 400 V line. If line voltage drops to 160 V, the percentage drop in heat output will be:

The figure shows a network of five capacitors connected to a 20 V battery. Calculate the charge acquired by each 10 µF capacitor.

The number of possible natural oscillations of air column in a pipe closed at one end of length 85 cm whose frequencies lie below 1250 Hz are (velocity of sound = 340 ms$^{-1}$)
A cylinder of fixed capacity 44.81 contains hydrogen gas at STP. What is the amount of heat needed to raise the temperature of the gas in the cylinder by 20° C? $ (R = 8.31 \, \text{J mol}^{-1} \, \text{K}^{-1}) $

A transformer of 100% efficiency has 200 turns in the primary and 40000 turns in the secondary. It is connected to a 220 V main supply and secondary feeds to a 100 K$\Omega$ resistance. The potential difference per turn is

Incident light of wavelength $ \lambda = 800 \, \text{nm} $ produces a diffraction pattern on a screen 1.5 m away when it passes through a single slit of width 0.5 mm. The distance between the first dark fringes on either side of the central bright fringe is

Column - I lists the waves of the electromagnetic spectrum. Column - II gives approximate frequency range of these waves. Match Column - I and Column - II and choose the correct match from the given choices.

The latent heat of vaporisation of water is 2240 J. If the work done in the process of vaporisation of 1 g is 168 J, the increase in internal energy is
Two narrow parallel slits illuminated by a coherent monochromatic light produces an interference pattern on a screen placed at a distance $ D $ from the slits. The separation between the dark lines of the interference pattern can be increased by
When a biconvex lens of glass of refractive index 1.5 is dipped in a liquid, it acts like a plane sheet of paper. This means the refractive index of the liquid is

In the A.C. circuit given below, voltmeters $ V_1 $ and $ V_2 $ read 100 V each. Find the reading of the voltmeter $ V_3 $ and the ammeter A.

Four resistors, each of resistance $ R $, are connected as shown in the figure below.

The conductivity of a semiconductor increases with increase in temperature because
A ball is moving in a circular path of radius 5 m. If tangential acceleration at any instant is $10 \, \text{m/s}^2$ and the net acceleration makes an angle of $30^\circ$ with the centripetal acceleration, then, the instantaneous speed is
A wire of length 2 m carries a current of 1 A along the x axis. A magnetic field $ \mathbf{B} = B_0 (i + j + k) $ tesla exists in space. The magnitude of the magnetic force on the wire is
The temperature of a wire is doubled. The Young's modulus of elasticity

Figure below shows a lens of refractive index, $ \mu = 1.4 $. $ C_1 $ and $ C_2 $ are the centres of curvature of the two faces of the lens of radii of curvature 4 cm and 8 cm respectively. The lens behaves as a

A negative charge particle is moving upward in a magnetic field which is towards north. The particle is deflected towards
A current $ I $ flows in an infinitely long wire with cross section in the form of semi-circular ring of radius 1 m. The magnitude of the magnetic induction along its axis is

A parallel plate capacitor having a dielectric constant 5 and dielectric strength $10^6 \, \text{V/m}$ is to be designed with a voltage rating of 2 kV. The field should never exceed 10% of its dielectric strength. To have the capacitance of 60 pF, the minimum area of the plates should be

If an electron in a hydrogen atom jumps from the third orbit to the second orbit, it emits a photon of wavelength $ \lambda $. When it jumps from the second to the first orbit, the corresponding wavelength of the photon will be: