List of top Physics Questions

When a piece of metal is illuminated by a monochromatic light of wavelength $\lambda$, then stopping potential is $3V_s$. When the same surface is illuminated by light of wavelength $2\lambda$, then stopping potential becomes $V_s$. The value of threshold wavelength for photoelectric emission will be:
An open organ pipe has a fundamental frequency of 300 Hz. The first overtone of a closed organ pipe has the same frequency as the first overtone of organ pipe. How long is each pipe?
Resistors $R_1$ and $R_2$ are placed in parallel as shown. If they have values of $5 \, \Omega$ and $10 \, \Omega$ respectively, their combined equivalent resistance is:
Resistors R1 and R2 are placed in parallel
A smooth inclined plane of length $L$ having inclination $\theta$ with the horizontal inside a lift which is moving down with retardation $\alpha$. The time taken by a body to slide down the inclined plane, from rest, will be:
The Young's modulus of brass and steel are $10 \times 10^{10} \, \text{Nm}^{-2}$ and $20 \times 10^{10} \, \text{Nm}^{-2}$, respectively. A brass wire and steel wire of the same length are extended by 1 mm under the same force. If the radii of the brass and steel wires are $R_B$ and $R_S$ respectively, then
A ball is thrown from the ground to clear a wall 3 m high at a distance of 6 m and falls 18 m away from the wall, the angle of projection of ball is
The chemical potential energy in gasoline is converted to kinetic energy in cars. If a car accelerates from zero to 60 km/h, compared to the energy necessary to increase the velocity of the car from 30 to 60 km/h, the energy necessary to increase the velocity of the car from 30 to 60 km/h is:
An air bubble starts rising from the bottom of a lake. Its diameter is 3.6 mm at the bottom and 4 mm at the surface. The depth of the lake is 250 cm and the temperature at surface is 40°C. What is the temperature at the bottom of the lake? Given atmospheric pressure = 76 cm of Hg and $g = 980 \, \text{cm/s^2$}
The momentum of a photon is $p$. The frequency associated with it is given by
The wavelength of the de-Broglie wave associated with a thermal neutron of mass $m$ at absolute temperature $T$ is given by (here, $K$ is the Boltzmann constant)
A transformer having efficiency of 90% is working on 200 V and 3 kW power supply. If the current in the secondary coil is 6 A the voltage across the secondary coil and the current in the primary coil respectively are
A drop of liquid of density $\rho$ is floating half-immersed in a liquid of density $d$. If $\sigma$ is the surface tension, then the diameter of the drop of the liquid is
Use the diagram below to answer the following questions. 40 spheres of equal mass make two rings of 20 spheres each. The ring on the right has a radius twice as large as the ring on the left.
If the position of the spheres approximates two uniformly dense rings, which of the following is the concerning a mass placed at position D?
40 spheres of equal mass make two rings of 20 spheres
In a car race, car A takes a time less than car B at the finish and passes the finishing point with speed \( v \) more than that of the car B. Assuming that both the cars start from rest and travel with constant accelerations \( a_1 \) and \( a_2 \) respectively. So, the value of \( v \) will be
An ideal fluid with pressure $p$ flows through a horizontal pipe with radius $r$. If the radius of the pipe is increased by a factor of 2, which of the following most likely gives the new pressure?
Two singly ionised isotopes, X and Y of the same element move at the same speed perpendicular to a uniform magnetic field. Isotope X follows a path of radius 3.43 cm while isotope Y moves along a path 3.35 cm in radius. What is the ratio of the two isotope masses, \( m_Y / m_X \)?
The time-period of a charged particle undergoing a circular motion in a uniform magnetic field is independent of its
Two identical wires A and B have the same length $L$ and carry the same current $I$. Wire A is bent into a circle of radius $R$ and wire B is bent to form a square of side $a$. If $B_1$ and $B_2$ are the values of magnetic induction at the centre of the square respectively, then the ratio $\frac{B_1{B_2}$ is}
The density of ice is $9.2 \times 10^2 \, \text{kg/m}^3$. If a chunk displaces $10^{-2} \, \text{m}^3$, the buoyant force on the ice is most nearly:
What are the units of the constant in the above equation?
In given circuit, all resistances are of $10 \Omega$. Current flowing through ammeter is
Which statement is correct for the given circuit?
A (+)vely charged particle is placed near an infinitely long straight conductor where there is zero gravity. Then
Two solenoids are given - 1st has 1 turn per unit length and 2nd has n turns per unit length. Ratio of magnetic fields at their centres is
Two point dipoles $p \hat{k}$ and $\frac{p}{2} \hat{k}$ are located at $(0,0,0)$ and $(1\, m , 0,2\, m )$ respectively. The resultant electric field due to the two dipoles at the point $(1 \,m , 0,0)$ is