List of top Physics Questions

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:
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 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:
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:
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
If the angle between two unit vectors $ \vec{A} $ and $ \vec{B} $ is $ \theta $, then \[ |\vec{A} + \vec{B}| = \]

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
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
If the electric field of an electromagnetic wave is increased by 100%, then the energy density of the wave increases by
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
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
The end points of a uniform wire are joined to a cell of emf $ E $ and internal resistance $ r $. Starting from the midpoint of the wire and moving in the direction of the current, the potential $ V(x) $ is measured at every point till the midpoint is reached again. The plot that represents the potential $ V $ against distance $ x $ moved from mid point is
The properties of a material required to make permanent magnets are
The correct statement among the following is
The particles with the following speed pass undeflected in the region of crossed fields
The magnitude of the magnetic field due to a circular coil of radius R carrying a current I at its centre is

A torch bulb rated as 4.5 W, 1.5 V is connected in the circuit as shown in the figure. If the bulb glows with maximum intensity, then the emf (E) is nearly

The force between two spheres with charges +7 $ \mu C $ and -5 $ \mu C $ is F. If each sphere is given an additional charge of +2 $ \mu C $, the new force of attraction will be

In the circuit given below, the charge on the capacitor $ C_1 $ is