List of top Physics Questions

A 1 cm straight segment of a conductor carrying 1 A current in $ x $-direction lies symmetrically at the origin of Cartesian coordinate system. The magnetic field due to this segment at point (1m, 1m, 0) is:

Two identical bodies of mass 1 kg each are moving towards each other with velocities of 5 m/s and 3 m/s, respectively. They collide elastically. What will be the velocity of the body initially moving at 5 m/s after the collision?

In space, the electric potential varies as $V = 20|r|$ volt, where $\vec{r} = x\hat{i} + y\hat{j} + z\hat{k}$ is the position vector. Then electric field in (N/C) at the point (4 m, 3 m, -5 m) is

A metal sheet is inserted between the plates of a parallel plate capacitor of capacitance C. If the sheet partly occupies the space between the plates, the capacitance:

The elastic potential energy stored in a copper rod of length one meter and area of cross-section $1 \, \text{mm}^2$ when stretched by 1 mm is:

A ball is thrown vertically upwards with a speed of $ 20 \, \text{m/s} $. What is the maximum height reached by the ball? Assume the acceleration due to gravity is $ g = 9.8 \, \text{m/s}^2 $.

The maximum speed of a boat in still water is 27 km/h. Now this boat is moving downstream in a river flowing at 9 km/h. A man in the boat throws a ball vertically upwards with speed of 10 m/s. Range of the ball as observed by an observer at rest on the river bank is _________ cm. (Take $ g = 10 \, {m/s}^2 $).

An electron (mass $9 \times 10^{-31}$ kg and charge $1.6 \times 10^{-19}$ C) moving with speed $c/100$ ($c$ = speed of light) is injected into a magnetic field of magnitude $9 \times 10^{-4}$ T perpendicular to its direction of motion. We wish to apply a uniform electric field $ \vec{E} $ together with the magnetic field so that the electron does not deflect from its path. (speed of light $c = 3 \times 10^8$ m/s):

Two gases A and B are filled at the same pressure in separate cylinders with movable pistons of radii $r_A$ and $r_B$ respectively. On supplying an equal amount of heat to both the cylinders, their pressures remain constant and their pistons are displaced by 16 cm and 9 cm respectively. If the change in their internal energies is the same, then the ratio $r_A / r_B$ is:

An electric dipole with dipole moment $p = 5 \times 10^{-6}$ Cm is aligned with the direction of a uniform electric field of magnitude $E = 4 \times 10^5$ N/C. The dipole is then rotated through an angle of $60^\circ$ with respect to the electric field. The change in the potential energy of the dipole is:

A parallel plate capacitor made of circular plates is being charged such that the surface charge density on its plates is increasing at a constant rate with time. The magnetic field arising due to displacement current is:

A pipe open at both ends has a fundamental frequency $f$ in air. The pipe is now dipped vertically in water drum to half of its length. The fundamental frequency of the air column is now equal to:

The kinetic energies of two similar cars A and B are 100 J and 225 J respectively. On applying brakes, car A stops after 1000 m and car B stops after 1500 m. If $F_A$ and $F_B$ are the forces applied by the brakes on cars A and B, respectively, then the ratio $ \frac{F_A}{F_B} $ is:

In a certain camera, a combination of four similar thin convex lenses are arranged axially in contact. Then the power of the combination and the total magnification in comparison to one lens will be, respectively:

The intensity of transmitted light when a polaroid sheet, placed between two crossed polaroids at $22.5^\circ$ from the polarization axis of one of the polaroids ($I_0$ is the intensity of polarised light after passing through the first polaroid):

Two cities X and Y are connected by a regular bus service with a bus leaving in either direction every T min. A girl is driving scooty with a speed of 60 km/h in the direction X to Y. She notices that a bus goes past her every 30 minutes in the direction of her motion, and every 10 minutes in the opposite direction. Choose the correct option for the period T of the bus service and the speed (assumed constant) of the buses.

A ball of mass 0.5 kg is dropped from a height of 10 m. The ball hits the ground and rises to a height of 1.5 m. The impulse imparted to the ball during its collision with the ground is : (Take $g = 9.8 \, \text{m/s}^2$)

A body weighs 48 N on the surface of the earth. The gravitational force experienced by the body due to the earth at a height equal to one-third the radius of the earth from its surface is:

Which of the following options represent the variation of photoelectric current with the property of light shown on the x-axis?

An unpolarized light beam travelling in air is incident on a medium of refractive index 1.73 at Brewster's angle. Then:

There are two inclined surfaces of equal length inclined at an angle of $45^\circ$ with the horizontal. One of them is rough and the other is perfectly smooth. A given body takes 2 times as much time to slide down on the rough surface than on the smooth surface. The coefficient of kinetic friction ($\mu_k$) between the object and the rough surface is close to :

A uniform rod of mass 20 kg and length 5 m leans against a smooth vertical wall making an angle of $60^\circ$ with it. The other end rests on a rough horizontal floor. The friction force that the floor exerts on the rod is (take $g = 10$ m/s$^2$):

In an oscillating spring mass system, a spring is connected to a box filled with sand. As the box oscillates, sand leaks slowly out of the box vertically so that the average frequency Ï‰(t) and average amplitude A(t) of the system change with time t. Which one of the following options schematically depicts these changes correctly?

A model for a quantized motion of an electron in a uniform magnetic field B states that the flux passing through the orbit of the electron is $ \phi = n h / e $ where $n$ is an integer, $h$ is Planck's constant and $e$ is the magnitude of electron's charge. According to the model, the magnetic moment of an electron in its lowest energy state will be ($m$ is the mass of the electron):

A photon and an electron (mass $m$) have the same energy $E$. The ratio $ \frac{\lambda_{\text{photon}}}{\lambda_{\text{electron}}} $ of their de Broglie wavelengths is: ($c$ is the speed of light)