List of top Physics Questions

Electric current produces :

(a) Explain the meaning of the statement ‘electric charge of a body is quantised’.
(b) Why can one ignore quantisation of electric charge when dealing with macroscopic i.e., large scale charges?

Figure shows a capacitor made of two circular plates each of radius 12 cm, and separated by 5.0 cm. The capacitor is being charged by an external source (not shown in the figure). The charging current is constant and equal to 0.15 A.

Calculate the capacitance and the rate of charge of potential difference between the plates.
Obtain the displacement current across the plates.
Is Kirchhoff’s first rule (junction rule) valid at each plate of the capacitor? Explain.

An artificial satellite revolves around earth in circular orbit of radius r with time period of orbit T. The satellite is made to stop in the orbit which makes it fall into earth. Time of fall of the satellite onto earth is given by

The I-V graph for a conductor at two different temperatures 100°C and 400°C is as shown in the figure. The temperature coefficient of resistance of the conductor is about (in per degree Celsius)

The I-V graph for a conductor at two different temp. 100°C and 400°C

In a potentiometer experiment, a cell of emf 1.5 V gives a balance point at 75 cm. If the cell is replaced by another cell and the balance point is at 60 cm, the emf of the second cell is:

If the earth shrinks such that its density becomes 8 times to the present value, then the new duration of the day in hours will be

A motor-cyclist moving towards a huge cliff with a speed of 18 kmh^-1, blows a horn of source frequency 325 Hz. If the speed of the sound in air is 330 ms^-1, the number of beats heard by him is

A Carnot engine operates between $ 500 \, \text{K} $ and $ 300 \, \text{K} $. If it absorbs $ 1000 \, \text{J} $ of heat from the source, the amount of work done by the engine is:

Two charges $ +5 \, \mu\text{C} $ and $ +5 \, \mu\text{C} $ are placed 1 m apart. What is the electric potential at the midpoint between them? (Take $k = 9 \times 10^9 \, \text{N.m}^2/\text{C}^2$).

A convex lens has a focal length of 20 cm. If an object is placed 30 cm from the lens, what is the image distance?

A current of 3 A flows through a wire of resistance 4 $\Omega$. What is the power dissipated in the wire?

A charged particle of mass $ m $ and charge $ q $ moves with a velocity $ \vec{v} $ perpendicular to a magnetic field $ \vec{B} $. The radius of the circular path it follows is:

A body of mass 2 kg is moving with a velocity of 10 m/s. What is its kinetic energy?

Two charges $ +4 \, \mu\text{C} $ and $ -4 \, \mu\text{C} $ are placed 2 m apart. What is the magnitude of the electric force between them? (Take $k = 9 \times 10^9 \, \text{N.m}^2/\text{C}^2$.

The acceleration due to gravity at a height h above the earths surface is $ 9m{{s}^{-2}}. $ If $ g=10\text{ }m{{s}^{-2}} $ on the earths surface, its value at a point at an equal distance h below the surface of the earth is

Phase difference between voltage and current in a capacitor in an ac circuit is

Two charges 5 × 10^–8 C and –3 × 10^–8 C are located 16 cm apart. At what point(s) on the line joining the to charges is the electric potential zero? Take the potential at infinity to be zero.

The volume occupied by the molecules contained in 4.5 kg water at STP, if the intermolecular forces vanish away is:

The angle between the electric lines of force and the equipotential surface is:

The x-t graph of a particle performing simple harmonic motion is shown in the figure. The acceleration of the particle at t=2s is:

The net impedance of circuit (as show figure) will be :

In a plane electromagnetic wave traveling in free space, the electric field component oscillates sinusoidally at a frequency of 2x10¹⁰ Hz and amplitude of 48 Vm^-1. Then the amplitude of the oscillating magnetic field is: (Speed of light in free space = 3x10⁸ ms^-1)

The venturi-meter works on:

In hydrogen spectrum, the shortest wavelength in the Balmer series is λ. The shortest wavelength in the bracket series is :