List of top Physics Questions

Two point charges $-q$ and $+ q$ are located at point's $(0, 0, - a)$ and, $(0, 0, a)$ respectively. The electric potential at a point $(0, 9, z)$, where $z > a$ is
Two identical piano wires have a fundamental frequency of $600 $ cycle per second when kept under the same tension. What fractional increase in the tension of one wires will lead to the occurrence of $6$ beats per second when both wires vibrate simultaneously?
A particle is projected up from a point at an angle $\theta$ with the horizontal direction. At any time $t$, if $p$ is the linear momentum, $y$ is the vertical displacement, $x$ is horizontal displacement, the graph among the following which does not represent the variation of kinetic energy $KE$ of the particle is
If the ratio of lengths, radii and Young's modulus of steel and brass wires shown in the figure are $a, b $ and $c$ respectively, the ratio between the increase in lengths of brass and steel wires would be
The two lenses of an achromatic doublet should have
A motor of power $P_0$ is used to deliver water at a certain rate through a given horizontal pipe. To increase the rate of flow of water through the same pipe $n$ times, the power of the motor is increased to $P_1$. The ratio of $P_1 $ to $P_0$ is
A body is projected vertically upwards at time $t=0$ and it is seen at a height $H$ at time $t_{1}$ and $t_{2}$ second during its flight. The maximum height attained is ( $g$ is acceleration due to gravity)
A soap bubble of radius $r$ is blown up to form a bubble of radius $2 r$ under isothermal conditions. If $T$ is the surface tension of soap solution, the energy spent in the blowing
A particle of mass $4 \,m$ explodes into three pieces of masses $m, m$ and $2 \,m$. The equal masses move along $X$-axis and $Y$-axis with velocities $4\, ms ^{-1}$ and $6\, ms ^{-1}$ respectively. The magnitude of the velocity of the heavier mass is
Transverse nature of light was confirmed by the phenomenon of
The driver of a car travelling with speed $30\, m/sec$ towards a hill sounds a horn of frequency $600\, Hz.$ If the velocity of sound in air is $330\, m/s,$ the frequency of reflected sound as heard by driver is
The de-Broglie wavelength of a neutron at $927^{\circ} C$ is $\lambda$. What will be its wavelength at $27^{\circ} C$ ?
A body of mass $5 \,kg$ makes an elastic collision with another body at rest and continues to move in the original direction after collision with a velocity equal to $\frac{1}{10}$ th of its original velocity. Then the mass of the second body is
Two sources $A$ and $B$ are sending notes of frequency $680 \,Hz$. A listener moves from $A$ and $B$ with-a constant velocity $u$. If the speed of sound in air is $340 \, ms^{-1}$ what must be the value of u so that he hears $10$ beats per second?
A clock pendulum made of invar has a period of $0.5 \, s$, at $20^{\circ}C$. If the clock is used in a climate where the temperature averages to $30^{\circ}C $, how much time does the clock lose in each oscillation? (For invar, $a = 9 \times 10^{-7} /^{\circ} C, g$ = constant)
A piece of metal weighs $45\, g$ in air and $25\, g$ in a liquid of density $1.5 \times 10^{3} \,kg - m ^{-3}$ kept at $30^{\circ} C$. When the temperature of the liquid is raised to $40^{\circ} C$, the metal piece weighs $27\, g$. The density of liquid at $40^{\circ} C$ is $1.25 \times 10^{3} \,kg - m ^{-3}$. The coefficient of linear expansion of metal is
Magnitudes of four pairs of displacement vectors are given. Which pair of displacement vectors, under vector addition, fails to give a resultant vector of magnitude $ 3\,cm $ ?
When a galvanometer is shunted by resistance S, its current capacity increases n times. If the same galvanometer is shunted by another resistance S', its current capacity will increase by n' is given by
The critical angle for total internal reflection in diamond is $ 24.5^{\circ} $ . The refractive index of the diamond is
An electrical cable having a resistance of $0.2 \,\Omega$ delivers $10\,kw$ at $200\,V\, D.C$. to a factory. What is the efficiency of transmission?
Huygens principle of secondary wavelets may be used to
Which out of following, cannot produce two coherent sources?
Assuming earth to be an inertial frame, an example for inertial frame observer is
The colloidal solution in which both the dispersed phase and dispersion medium arc liquids called
Two radioactive substances $A$ and $B$ have decay constants $5\, \lambda$ and $\lambda$ respectively. At $t=0$ they have the same number of nuclei. The ratio of number of nuclei of $A$ to those of $B$ will be $\left(\frac{1}{e}\right)^{2}$ after a time interval