List of top Physics Questions

An object is placed at a distance of $40\, cm$ from a concave mirror of focal length $15\, cm$. If the object is displaced through a distance of $20\, cm$ towards the mirror, the displacement of the image will be
A pendulum is hung from the roof of a sufficiently high building and is moving freely to and fro like a simple harmonic oscillator. The acceleration of the bob of the pendulum is $20 \, m/s^{-2}$ at a distance of $5 \,m$ from the mean position. The time period of oscillation is
An inductor $20\, mH$, a capacitor $100\, \mu F$ and a resistor $50 \, \Omega$ are connected in series across a source of emf, $V\, = \,10 \,sin\, 314\, t$. The power loss in the circuit is
A carbon resistor of $(47 \pm 4.7) \, k \Omega$ is to be marked with rings of different colours for its identification. The colour code sequence will be

A set of ‘n’ equal resistors, of value \('R'\) each, are connected in series to a battery of emf ‘E’ and internal resistance ‘R' The current drawn is \(I\) . Now, the ‘n’ resistors are connected in parallel to the same battery. Then the current drawn from the battery becomes \(10 \,I\) . The value of ‘n’ is

A student measured the diameter of a small steel ball using a screw gauge of least count $0.001\, cm$. The main scale reading is $5\, mm$ and zero of circular scale division coincides with $25$ divisions above the reference level. If screw gauge has a zero error of - $0.004\, cm$, the correct diameter of the ball is
An astronomical refracting telescope will have large angular magnification and high angular resolution, when it has an objective lens of
What modulation index and side bands are produced when a message of frequency $ 10 \,kHz $ and peak voltage of $ 10 $ volts is used to modulate a carrier frequency of $ 1 \,MHz $ and peak voltage of 20 volts ?
The resistance of the platinum wire of a platinum resistance thermometer at the ice point is $ 5\,\Omega $ and at steam point is $ 5.23\,\Omega $ . When the thermometer is inserted in a hot bath, the resistance of the platinum wire will be $ 5.795\,\Omega $ . Calculate the temperature of the bath.
An electric bulb, a capacitor, a battery and a switch are all in series in a circuit. How does the intensity of light vary when the switch is turned on ?
What will be the current flowing through the $6 \,K \Omega$ resistor in the circuit shown, where the breakdown voltage of the zener is $6\, V$ ?
The electrostatic force between the metal plate of an isolated parallel plate capacitor $C$ having charge $Q$ and area $A$, is
If Young?s double slit experiment is done with white light, which of the following statements will be true ?
A large number of liquid drops each of radius r coalesce to from a single drop of radius R. The energy released in the process is converted into kinetic energy of the big drop so formed. The speed of the big drop is (given, surface tension of liquid T, density $\rho$)
A metal disc of radius $100 \,cm$ is rotated at a constant angular speed of $60$ rad/s in a plane at right angles to an external field of magnetic induction $0.05\, Wb/m^2$. The emf induced between the centre and a point on the rim will be
One mole of a mono-atomic ideal gas undergoes a quasi-static process, which is depicted by a straight line joining points $(V_0, T_0)$ and $(2V_0, 3T_0)$ in a $V-T$ diagram. What is the value of the heat capacity of the gas at the point $(V_0, T_0)$ ?
A tuning fork is used to produce resonance in glass tube. The length of the air column in the tube can be adjusted by a variable piston, A room temperature of $27^{\circ} C$ two successive resonances are produced at $20\, cm$ and $73\, cm$ column length. If the frequency of the tuning for is $320\, Hz$, the velocity of sound in air at $27^{\circ} C$
The force of repulsion between two identical positive charges when kept with a separation 'r' in air is 'F' Half the gap between the two charges is filled by a dielectric slab of dielectric constant = 4. Then the new force of repulsion between those two charges becomes
In the circuit shown, inputs $A$ and $B$ are in states ?$1$? and ?$0$? respectively. What is the possible stable state of the outputs ?$X$? and ?$Y$? ?
A 100 W bulb is connected to an AC source of 220 V, 50 Hz. Then the current flowing through the bulb is
A charge q is accelerated through a potential difference V. It is then passed normally through a uniform magnetic field, where it moves in a circle of radius r. The potential difference required to move it in a circle of radius 2r is
A mass �m� on the surface of the Earth is shifted to a target equal to the radius of the Earth. If �R� is the radius and �M� is the mass of the Earth, then work done in this process is
The ratio of radii of the first three Bohr orbits is

The temperature of equal masses of three different liquids A, B and C are \(12^{\circ}C\), \(12^{\circ}C\) and \(28^{\circ}C\) respectively. The temperature when A and B are mixed is \(16^{\circ}C\) and when B and C are mixed is \(23^{\circ}C\). The temperature when A and C are mixed is

The length of elastic string, obeying Hooke�s law is $\ell_{1}$ metres when the tension $4N$ and $\ell_{2}$ metres when the tension is $5N$. The length in metres when the tension is $9N$ is -