List of top Physics Questions

Which of the following is unitless quantity ?

If there is a charge on the surface of sphere, what will be the electric field inside the sphere?

Two taps supply water to a container, one at the temperature of $20^{\circ}C$ at the rate of $2 \,$kg/minute and another at $80^{\circ}C$ at the rate of $1$ kg/minute. If the container gets water from the two taps simultaneously for $10$ minutes, then the temperature of water in the container is
For which of the following dispersive power is zero ?
The mass of moon is 1% o f mass of earth. The ratio of gravitational pull of earth on moon and that of moon on earth will be
In two different systems of units, acceleration is represented by the same number while a velocity is represented by numbers in the ratio $1 : 3$. The ratios of unit of length and time are, respectively,
The control rods used in a nuclear reactor can be made up of
Quantisation of charge implies

Given below are two statements, one is labelled as Assertion A and the other is labelled as Reason R
Assertion (A): Propagation of light through an optical fibre is due to total internal reflection taking place at the core-cladding interface 

Reason (R) : Refractive index of the material of the core of the optical fibre is greater than that of air.

In the light of the above statements, choose the correct answer from the options given below

Current flows through uniform, square frames as shown in the figure. In which case is the magnetic field at the centre of the frame not zero?
Three point charges +q, -q and +q are placed at points (x = 0, y = a, z = 0), (x = 0, y = 0, z = 0) and (x = a, y = 0, z = 0) respectively. The magnitude and direction of the electric dipole moment vector of this charge assembly are
The angle of dip at a place is $ {{37}^{o}} $ and the vertical component of the earths magnetic field is $ 6\times {{10}^{-5}}T. $ The earths magnetic field at this place is $ (tan\text{ }{{37}^{o}}=3/4) $
A charged oil drop is suspended in a uniform electric field of $3 \times 10^{4}\, V / m$ so that it neither falls nor rises. The charge on the drop will be (take the mass of the drop is $9.9 \times 10^{-15} \,kg$ and $g=10 \,ms ^{-2}$ )
In a hall, a person receives direct sound waves from a source $120 \,m$ away. He also receives waves from the same source which reach him after being reflected from the $25\, m$ high ceiling at a point half-way between them. The two waves interfere constructively for wavelengths (in metre) of
In a YDSE bi-chromatic light of wavelengths 400 nm and 560 nm are used. The distance between the slits is 0.1 mm and the distance between the plane of the slits and the screen is 1 m. The minimum distance between two successive regions of complete darkness is
When a rod is heated but prevented from expanding the stress developed is independent of:
A copper wire and a steel wire of the same diameter and length are joined end to end and a force is applied which stretches their combined length by $1 \,cm$. Then the two wires will have:
The work done by a particle moving with a velocity of $0.7\, c$ (where $c$ is the velocity of light) in empty space free of electromagnetic field and far away from all matter is :
An engine is moving on a circular path of radius $100\, m$ with a speed of $20 \,m / s$. What will be the frequency observed by an observer standing stationary at the centre of rircular path when the engine blows a whistle of frequency $500 \,Hz$ ?
A body of mass $2\, kg$ has an initial velocity of $3 m / s$ along $OE$ and it is subjected to a force of $4\, N$ in a direction perpendicular to $O E$. The distance of body from $O$ after $4 s$ will be :
If the velocity of light c, gravitational constant G and Planck's constant $ h, $ are chosen as fundamental units, the dimensional formula of length L in the new system is:
A body slides down a frictionless inclined plane starting from rest. If $S_n$ and $S_{n+1}$ be the distance travelled by the body during nth and $(n + 1) {th}$ seconds, then the ratio $\frac{S_{n+1}}{S_n}$ is
In an interference arrangement similar to Young's double-slit experiment, the slits $S_1$, and $S_2$ are illuminated with coherent microwave sources, each of frequency $10^6$ Hz. The sources are synchronized to have zero phase difference. The slits are separated by a distance d = 150.0 m. The intensity I$(\theta)$ is measured as a function of $\theta$, where $\theta$ is defined as shown. If $I_0$ is the maximum intensity, then I$(\theta)$ for $0 \le \theta \le$90$^{\circ}$ is given by
If 'A' is areal velocity of a planet of mass M, its angular momentum is
A mariners compass is used