List of top Physics Questions

The radius of innermost orbit of a hydrogen atom is 5.3x10^-11 m. What is the radius of the third allowed orbit of the hydrogen atom?

Calculate the maximum acceleration of a moving car so that a body lying on the floor of the car remains stationary. The coefficient of static friction between the body and the floor is 0.15 (g=10ms^-2).

A horizontal bridge is built across a river. A student standing on the bridge throws a small ball vertically upwards with a velocity \(4\ ms^{-1}\). The ball strikes the water surface after \(4s\). The height of bridge above water surface is
(Take: \(g=10\ ms^{-2}\))

A satellite is orbiting just above the surface of the earth with period T. If d is the dependent of the earth and G is the universal constant of gravitation, the quantity 3π/Gd respectively:

Two thin lenses are of same focal length (f), but one is convex and the other is concave. When they are placed in opposite with each other, the equivalent focal of the combination will be:

For the following logic circuit, the truth table is:

As shown in the figure, a very long conducting wire is bent in a semi-circular shape from A to B. The magnetic field at point P for steady current configuration is given by:

The resistance of platinum wire at 0°C is 2Ω and 6.89Ω at 80°C. The temperature coefficient of resistance of the wire is:

An electric dipole is placed as shown in the figure.

The electric potential (in 102 V) at point P due to the dipole is (ε₀ = permittivity of free space and \(\frac{1}{4\pi\epsilon_0}=K\)):

A wire carrying a current I along the positive x-axis has length L. It is kept in a magnetic field \(\vec{B}=(2\vec{i}+3\vec j-4\vec k)T\). The magnitude of the magnetic force acting on the wire is:

Two transparent media. A and B are separated by a plane boundary. The speed of light in those media are 1.5 × 10⁸ m/s and 2.0 × 10⁸ m/s, respectively. The critical angle for a ray of light for these two media is:

A ball is projected with a velocity, 10 ms-1, at an angle of 60° with the vertical direction. Its speed at the highest point of its trajectory will be:

A nucleus of mass number 189 splits into two nuclei having mass number 125 and 64. The ratio of radius of two daughter nuclei respectively is:

A big circular coil of 1000 turns and average radius 10 m is rotating about its horizontal diameter at 2 rad s^-1. If the vertical component of earth’s magnetic field at that place is 2 × 10^-5 T and electrical resistance of the coil is 12.56 Ω, then the maximum induced current in the coil will be:

Two pendulums of length 121 cm and 100 cm start vibrating in phase. At some instant, the two are at their mean position in the same phase. The minimum number of vibrations of the shorter pendulum after which the two are again in phase at the mean position is:

Choose the correct answer from the options given below:

List – I	List – II
(a) Gravitational constant	(i) [L²T^-2]
(b) Gravitational potential energy	(ii) [M^-1L³T^-2]
(c) Gravitational potential	(iii) [LT^-2]
(d) Gravitational intensity	(iv) [ML²T^-2

A series LCR circuit with inductance 10 H, capacitance 10 μF, resistance 50 Ω is connected to an ac source of voltage, V =200 sin(100 t) volt. If the resonant frequency of the LCR circuit is v_o and the frequency of the ac source is v, then:

Given below are two statements: One is labelled as Assertion (A) and the other is labelled as Reason (R).
Assertion (A): The stretching of a spring is determined by the shear modulus of the material of the spring.
Reason (R): A coil spring of copper has more tensile strength than a steel spring of same dimensions.
In the light of the above statements choose the most appropriate answer from the options given below:

The area of rectangular field (in m²) of length 55.3 m and breadth 25 m after rounding off the value for correct significant digits is:

If a soap bubble expands, the pressure inside the bubble:

When two monochromatic light of frequency ν and \(\frac{ν}{2}\) are incident on a photoelectric metal, their stopping potential becomes \(\frac{V_s}{2}\) and V_s respectively. The threshold frequency for this metal is:

Two resistors of resistances, 100 Ω and 200 Ω are connected in parallel in an electrical circuit. The ratio of thermal energy developed in 100 Ω to that in 200 Ω in a given time is

A light ray falls on a glass surface of refractive index √3, at an angle 60°. The angle between the refracted and reflected rays would be:

Plane angle and solid angle have:

In the given nuclear reaction, the element X is: 22 11 Na → X + x₂ + v