List of top Physics Questions

If the galvanometer G does not show any deflection in the circuit shown, the value of R is given by:

In a Young's double slit experiment, a student observes 8 fringes in a certain segment of screen when a monochromatic light of 600 nm wavelength is used. If the wavelength of light is changed to 400 nm, then the number of fringes he would observe in the same region of the screen is

An electric lift with a maximum load of 2000 kg (lift + passengers) is moving up with a constant speed of 1.5 ms^-1. The frictional force opposing the motion is 3000N. The minimum power delivered by the motor to the lift in watts is: (g =10 ms^-2)

The peak voltage of the ac source is equal to:

A long solenoid of radius 1 mm has 100 turns per mm. If 1 A current flows in the solenoid, the magnetic field strength at the centre of the solenoid is:

What is the focal length of double concave lens kept in air with two spherical surfaces radii R₁= 20 cm and R₂ = 40 cm. Take refractive index of lens n = \(\frac{5}{3}\)

A bar of m = 1.00 kg and length l = 0.20 m is lying on a horizontal frictionless surface. One end of the bar is pivoted so that the bar is free to rotate in the vertical plane. a small m = 0.10 kg is moving on the same horizontal surface with 5.00 ms^-1 speed on its path which is perpendicular to the bar. Its hits the bar at a distance \(\frac{L}{2}\) from the pivoted end and return back on the same path with speed v. After this elastic collision, the bar rotates with an angular velocity ω. Which of the following statement is correct?

The half life of a radioactive substance is 20 minutes. In how much time the activity of substance drops to \((\frac{1}{16})^{th}\) of its initial value?

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:

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:

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:

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:

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?

A carnot engine has an efficiency of 50% when its source is at a temperature 327°C. The temperature of the sink is:

Let a wire be suspended from the ceiling (rigid support) and stretched by a weight W attached at its free end. The longitudinal stress at any point of cross-sectional area A of the wire is:

Light travels a distance x in time t1 in air and 10x in time t2 in another denser medium. What is the critical angle for this medium?

A 12V, 60W lamp is connected to the secondary of a step down transformer, whose primary is connected to ac mains of 220V. Assuming the transformer to be ideal, what is the current in the primary winding?

The magnitude and direction of the current in the following circuit is

If \(∮_s\overrightarrow{E}.\overrightarrow{dS}=0\) over a surface, then:

A football player is moving southward and suddenly turns eastward with the same speed to avoid an opponent. The force that acts on the player while turning is:

The work functions of Caesium (Cs), Potassium (K) and Sodium (Na) are 2.14eV, 2.30 eV and 2.75eV respectively. If incident electromagnetic radiation has an incident energy of 2.20eV, which of these photosensitive surfaces may emit photoelectrons?

Given below are two statements:
Statement I: Photovoltaic devices can convert optical radiation into electricity.
Statement II: Zener diode is designed to operate under reverse bias in breakdown region.
In the light of the above statements, choose the most appropriate answer from the options given below:

The net magnetic flux through any closed surface is:

A full wave rectifier circuit consists of two p-n junction diodes, a centre-tapped transformer, capacitor and a load resistance. Which of these components remove the ac ripple from the rectified output?

The amount of energy required to form a soap bubble of radius 2 cm from a soap solution is nearly: (surface tension of soap solution = 0.03 Nm^-1)