List of top Physics Questions

Three thin metal rods, each of mass $M$ and length $L$, are welded to form an equilateral triangle. The moment of inertia of the composite structure about an axis passing through the centre of mass of the structure and perpendicular to its plane is

There are two identical small holes on the opposite sides of a tank containing a liquid. The tank is open at the top. The difference in height between the two holes is $h$. As the liquid comes out of the two holes, the tank will experience a net horizontal force proportional to

The potential difference across the $3 \,\Omega$ resistor shown in figure is

The magnetic flux linked with the coil varies with time as $\phi = 3t^2+4t+9$.The magnitude of the induced emf of $2s$ is

The force $F$ is given by expression $F=A \cos (B x)+C \sin (D t)$, where $x$ is the displacement and $t$ is the time. Then dimension of $\frac{D}{B}$ are same as that of

The energy gap of silicon is $1 .1 4 \,eV$. The maximum wavelength at which silicon starts energy absorption, will be $(h = 6.62 \times 10^{-34}\, J\, s$; $c = 3 \times 10^8\, ms^{ -1})$

The distance between the two successive nodes is

The current passing through an inductor coil of 5H is decreasing at the rate of 2A/s, the emf developed across the coil is

The current and voltage in AC circuit are given by $ I=5\sin \left( 100t-\frac{\pi }{2} \right)A $ and $ V=200\sin (100t) $ volt. The power dissipated in the circuit will be

Polaroid glass is used in sun glasses because

If $x, v$ and $a$ denote the displacement, the velocity and the acceleration of a particle executing simple harmonic motion of time period $T$, then, which of the following does not change with time?

Moment of inertia of a uniform rod of length $L$ and mass $M$, about an axis passing through $L/4$ from one end and perpendicular to its length is

In an intrinsic semiconductor band gap is $1.2\, eV$ then ratio of number of charge carriers at $600\, K$ and $300\, K$ is

The de-Broglie wavelength equation has significance for any microscopic and submicroscopic particles. de-Broglie wavelength is inversely proportional to the mass of the object its velocity is constant.

Resolving power of a telescope depends only on wavelength. This is proportional to square of wavelength.

If optical density of a substance is more than that of water then the mass density of substance can be less than water. Optical density and mass density are not related.

Heat from the sun reaches the earth by convection. Air can be heated only by convection.

Electrons move from a region of higher potential to a region of lower potential. An electron has less potential energy at a point where potential is higher and vice-versa.

At the centre of earth a body has centre of mass, but no centre of gravity. This is because $g = 0$ at the centre of earth.

A body can be at rest even when it is under the action of any number of external forces. Vector sum of all the external forces is zero.

In a common emitter $(CE)$ amplifier having a voltage gain $G$, the transistor used has transconductance $0.03 \,mho$ and current gain $25$. If the above transistor is replaced with another one with transconductance $0.02$ $mho$ and current gain $20$, the voltage gain will be :

In which of the following viscous force does not depend ?

A spherical shell is shown in figure. What is the electric field inside the shell?

Positive rays made of

$X$-rays was discovered by