List of top Physics Questions

A body of mass 2 kg is moving with a velocity of 3 m/s. What is its kinetic energy?

Two cells of emf 10 V each, two resistors of 20 $ \Omega $ and 10 $ \Omega $, and a bulb B of 10 $ \Omega $ resistance are connected together as shown in the figure. Find the current that flows through the bulb.

A battery of emf $ E $ and internal resistance $ r $ is connected to a rheostat. When a current of 2A is drawn from the battery, the potential difference across the rheostat is 5V. The potential difference becomes 4V when a current of 4A is drawn from the battery. Calculate the value of $ E $ and $ r $.

In an intrinsic semiconductor, carrier’s concentration is $ 5 \times 10^8 \ \text{m}^{-3} $. On doping with impurity atoms, the hole concentration becomes $ 8 \times 10^{12} \ \text{m}^{-3} $.

[(a)] Identify (i) the type of dopant and (ii) the extrinsic semiconductor so formed.

[(b)] Calculate the electron concentration in the extrinsic semiconductor.

In the given figure, three identical bulbs P, Q, and S are connected to a battery.

[(i)] Compare the brightness of bulbs P and Q with that of bulb S when key K is closed.

[(ii)] Compare the brightness of the bulbs S and Q when the key K is opened.
Justify your answer in both cases.

A wire has a resistance of $ 10 \, \Omega $ at $ 20^\circ \text{C} $. If the temperature coefficient of resistance of the material is $ 0.004 \, \text{per}^\circ \text{C} $, what is the resistance of the wire at $ 50^\circ \text{C} $?

A thin plano-concave lens with its curved face of radius of curvature R is made of glass of refractive index $ n_1 $. It is placed coaxially in contact with a thin equiconvex lens of same radius of curvature of refractive index $ n_2 $. Obtain the power of the combination lens.

A simple pendulum has a length of $ L = 2 \, \text{m} $. What is the time period of the pendulum? (Assume $ g = 9.8 \, \text{m/s}^2 $)

A projectile is launched with an initial velocity of $ 20 \, \text{m/s} $ at an angle of $ 30^\circ $ with the horizontal. What is the maximum height reached by the projectile? (Take $ g = 10 \, \text{m/s}^2 $)

In the figure, curved lines represent equipotential surfaces. A charge $ Q $ is moved along different paths A, B, C, and D. The work done on the charge will be maximum along the path:

Show the refraction of light wave at a plane interface using Huygens' principle and prove Snell's law.

If an electron in the excited state falls to ground state, a photon of energy 5 eV is emitted, then the wavelength of the photon is nearly

A charge $ Q $ is distributed over two concentric hollow spheres of radii $ r $ and $ R $ ($ R>r $) such that their surface charge densities are equal. Find: \begin{enumerate} \item the electric field, and \item the potential at their common center. \end{enumerate}

A body of mass 100 g is moving in a circular path of radius 2 m on a vertical plane as shown in the figure. The velocity of the body at point A is 10 m/s. The ratio of its kinetic energies at point B and C is: (Take acceleration due to gravity as 10 m/s$^2$)

Find the magnetic field at a point 5 cm away from a long straight wire carrying current $ I = 20\,A $.

A concave mirror has a focal length of 20 cm. An object is placed 60 cm in front of the mirror. Find the image distance.

The electric field in a region is given by $ \vec{E} = 40x \hat{i} \, \text{N/C}. $ Find the amount of work done in taking a unit positive charge from a point (0, 3m) to the point (5m, 0).

What is Ferromagnetism? Explain it on the basis of domain theory.

State Kirchhoff's law related to electrical circuits. In the given metre bridge, balance point is obtained at D. On connecting a resistance of 12 ohm parallel to S, balance point shifts to D'. Find the values of resistances R and S.

A voltmeter of resistance 1000 $ \Omega $ can measure up to 25 V. How will you convert it so that it can read up to 250 V?

A body starts from rest and moves with constant acceleration. If it covers a distance of $ 40 \, \text{m} $ in 4 seconds, then its acceleration is:

A projectile is fired with an initial velocity $ u $ at an angle $ \theta $ to the horizontal. The time of flight is $ T $. What is the maximum height $ H $ reached by the projectile?

A proton moving with velocity $ V $ in a non-uniform magnetic field traces a path as shown in the figure. The path followed by the proton is always in the plane of the paper. What is the direction of the magnetic field in the region near points P, Q, and R? What can you say about relative magnitude of magnetic fields at these points?

A simple pendulum has a time period of 2 s on Earth's surface. What is its time period at a height equal to the Earth's radius (R)? (Acceleration due to gravity at height h is $ g_h = \frac{g}{(1 + h/R)^2} $).

Distinguish between interference and diffraction of light. A double slit arrangement produces interference fringes for sodium light of wavelength 589 nm, that are 0.20 degree apart. What is the angular fringe separation if the entire arrangement is immersed in water? (R.I. of water = 1.33)