List of top Physics Questions

A velocity of a particle at an instant is $10\, m / s$. After $3\, s$ its velocity will become $16\, m / s$. The velocity at $2\, s$, before the given instant will be :

A particle moves with a velocity $(5i -3j + 6k) ms^{-1}$ undre the influence of a constant force $F=(10 i +10 j +20 K)N .$ The instantaneous power applied to the particle is

A weight $w$ is suspended from the midpoint of a rope, whose ends are at the same level. In order to make the rope perfectly horizontal, the force applied to each of its ends must be:

The energy spectrum of $\beta$-particles [number N(E) as a function of $\beta$-energy E] emitted from a radioactive source is :

In a series resonant $LCR$ circuit, the voltage across $R$ is $100$ volts and $R = 1\,\Omega$ with $C = 2\mu F$. The resonant frequency $\omega$ is $200$ rad/s. At resonance the voltage across $L$ is :

In a common-base mode of a transistor, the collector current is 5.488 mA for an emitter current of 5.60 mA. The value of the base current amplification factor ($\beta$) will be :

A string is stretched between fixed points separated by $75.0\, cm$. It is observed to have resonant frequencies of $420\, Hz$ and $315\, Hz$. There are no other resonant frequencies between these two. Then, the lowest resonant frequency for this string is :

Which of the following units denotes the dimensions $[ML^2/Q^2],$ where $Q$ denotes the electric charge ?

A long solenoid has $200$ turns per cm and carries a current $i$. The magnetic field at its centre is $6.28 \times 10^{-2}$ weber/$m^2$. Another long solenoid has 100 turns per cm and it carries a current $i/3$. The value of the magnetic field at its centre is:

A large ship can float but a steel needle sinks because of:

A lens is made of flint glass (refractive index $=1.5$ ). When the lens is immersed in a liquid of refractive index $1.25$, the focal length :

An object is kept on a smooth inclined plane of 1 in $l$. The horizontal acceleration to be imparted to the inclined plane so that the object is stationary relative to the incline is

A point source emits sound equally in all directions in a non-absorbing medium. Two point P and Q are at distances of 2 m and 3 m respectively from the source. The ratio of the intensities of the waves at P and Q is

If $E$ = energy, $G$ = gravitational constant, $I$ = impulse and $M$ = mass, the dimensions of $\frac{GIM^{2}}{E^{2}}$ are same as that of

Which of the following expressions is that of a harmonic progressive wave?

Two parallel large thin metal sheets have equal surface charge densities $\left(\sigma=26.4\times10^{-12} c m^{2}\right)$ of opposite signs. The electric field between these sheets is

A hole is in the bottom of the tank having water. If total pressure at the bottom is $3$ atm $(1 \,atm = 10^{5}\, Nm^{-2})$, then velocity of water flowing from hole is

The length, breadth and thickness of a block are given by I= 12 cm, b = 6 cm and t = 2.45 cm. The volume of the block according to the idea of significant figures should be

Acceleration due to gravity at earth's surface is g $ms^{-2}$ Find the effective value of gravity at a height of 32 km from sea level $(R_e = 6400\, km)$

Two waves, represented by the following equations, are travelling in the same medium $\hspace30mm y_1 = 5 sin \, 2 \pi (75 t - 0.25 x)$ $\hspace30mm y_2 = 10 sin \, 2 \pi (150 t - 0.50 x)$ The intensity $\frac{I_2}{I_1}$ of two waves is

A body is just being revolved in a vertical circle of radius R with a uniform speed. The string breaks when the body is at the highest point. The horizontal distance covered by the body after the string breaks is

A judo fighter in order to throw his opponent on to the mat tries to initially bend his opponent and then rotate him around his hip. As the mass of opponent is brought closer to the fighter?s hip, the force required to throw the opponent is reduced.

${ }_{92}^{238} U$ has $92$ protons and $238$ nucleons. It decays by emitting an alpha particle and becomes:

If a street light of mass $M$ is suspended from the end of a uniform rod of length $L$ in different possible patterns as shown in figure, then :

An amplifier has a voltage gain $A_{v}=1000$. The voltage gain in $dB$ is :