List of top Physics Questions

The change in internal energy when 20 g of a gas is heated from $ 25^\circ C $ to $ 35^\circ C $ at constant volume is: Options:
The gravitational potential energy of a system of three masses $ m $, $ 2m $, and $ 3m $ placed at the three vertices of an equilateral triangle of side $ a $ is Options:
A metal wire with circular cross section and length one metre is pulled with tensile force of 1000 N on each side. For the wire to be stretched not more than 0.25 cm, the minimum diameter of the wire required is:
(Young's modulus of the metal $= 10^{11}$ \text{ Pa, take } $\sqrt{\pi} = 1.77$)
The temperature of the earth without the greenhouse effect will be: Options:
A solid sphere and a solid cylinder roll down without slipping along an inclined plane. If they start from rest from the top of the inclined plane, the ratio of the velocities of the solid sphere and solid cylinder when they reach the bottom of the inclined plane is:
A solid sphere of mass 2 kg is rolling without slipping on a horizontal surface with a velocity 5 m/s. The rotational kinetic energy of the sphere is: Options:
The maximum acceleration with which a body of mass 200 kg is lowered into a well using a rope having a breaking force of 50 kg-wt is (Acceleration due to gravity = 10 $ ms^{-2} $)
A body of mass 2 kg is on an inclined plane of inclination 30° and coefficient of friction is $ \frac{1}{\sqrt{3}} $. The minimum force required to move the body up the inclined plane is: \[ \text{(Acceleration due to gravity = 10 ms}^{-2}\text{)} \] Options:
A pendulum of time period one second is losing its mechanical energy due to damping. Its mechanical energy at time $ t = 0 $ is 45 J. After completing 15 oscillations, its mechanical energy is 15 J. The ratio of the damping constant and the mass of the object making damped oscillations is:
A toy of mass 20 g at rest acquires a velocity $ (3\hat{i} - 2\hat{j}) $ ms$ ^{-1} $ in 2 seconds. Then the power of the toy is
A ball is dropped from some height and after first collision with the ground if it reaches $ \frac{3}{4} $th of its original height, then the % loss of its energy is: Options:
The potential difference across the ends of a conductor is $ (50 \pm 3) $ V and the current through it is $ (5 \pm 0.1) $ A. The percentage error in the measurement of the resistance of the conductor is: Options:
If the angle between two unit vectors $ \vec{A} $ and $ \vec{B} $ is $ \theta $, then \[ |\vec{A} + \vec{B}| = \]
The time taken by a boat to travel upstream to a certain distance and return back is 14 hours. If the velocity of boat in still water is 35 kmh$ ^{-1} $ and velocity of the stream is 5 kmh$ ^{-1} $, the distance travelled by the boat before it returns is
The velocity (v) of a particle starting from rest increases linearly with time (t) as $ v = 4t $, where v is in $ ms^{-1} $ and t is in second. The distance covered by the particle in the first 4 seconds is
A monochromatic light wave is incident normally on a glass slab of thickness as shown in the figure. The refractive index of the slab increases linearly from n1 to n2 over the height of h. Which of the following statements is/are true about the light wave emerging out of the slab?
Monochromatic light wave
Monochromatic light wave
 

The electric potential at a point is given by $ V = \left(-5x + 3y + \sqrt{15z} \right) \, \text{volt}$.
The magnitude of the electric field at that point is

The attenuation of a signal is compensated by
The time period of revolution of an electron in an orbit of principal quantum number $ n $ is $ T $. If the relation between time period and principal quantum number is $ T \propto n^3 $, then $ x = $
A radioactive element A with half life 3 hours decays to a stable element B. After a time $ t $, the ratio of A and B atoms is 1:16 then the time $ t $ in hours is
A capacitor and a resistor are connected in series to an ac source of variable frequency. When the frequency of the ac source becomes $ \frac{1}{3} $rd of its initial value, the current in the circuit decreases by 50%. The power factor of the circuit at the initial frequency is
If the electric field of an electromagnetic wave is increased by 100%, then the energy density of the wave increases by
If L is the inductance and C is the capacitance, then the frequency of a transistor oscillator is directly proportional to
When the voltage applied across a reverse biased p-n junction diode is increased, then the diffusion current
An electron, a proton and an alpha particle are moving with same kinetic energy. If $ \lambda_1, \lambda_2, \lambda_3 $ are the de Broglie wavelengths of the electron, proton and alpha particle respectively, then