List of top Physics Questions

The energy of spectral line of lowest frequency in Lyman series of $Li^{2+}$ spectrum is x J. The energy of second spectral line in Balmer series of $He^{+}$ spectrum is y J. The ratio of x and y is

A 1200 kg artificial satellite is in an orbit of radius $2R_{E}$ about the earth. The energy required to transfer it to an orbit of radius $3R_{E}$ is ($g=10\text{ms}^{-2}$, $R_{E}=6400 \text{ km}$)

Calculate the amount of work done in spraying a drop of a liquid of radius 1 mm into million identical droplets under isothermal conditions. [surface tension of liquid $=550\times10^{-3}\text{Nm}^{-1}$]

In simple harmonic motion, at mean position

The rms speed of oxygen molecule at some temperature is $150 \text{ ms}^{-1}$. Then the rms speed of hydrogen molecule at the same temperature is

The refractive index of water is $\frac{4}{3}$ and that of glass is $\frac{3}{2}$. The refractive index of glass with respect to water is

Electromagnetic waves do not transport

For the same angle of incidence, the angles of refraction of light ray in different media A, B, C are $35^{\circ}$, $25^{\circ}$, $15^{\circ}$. If $V_{A}, V_{B}, V_{C}$ are velocities of light in A, B, C media respectively, then

Two identical balls each of mass $\frac{40}{3}$ g carry equal and opposite charge. They are suspended from a horizontal plate by silk threads each of length 1 m with a separation of 1.5 m between points of suspension. At equilibrium, if the distance between the balls is 30 cm then magnitude of charge on each ball is (Acceleration due to gravity $= 10 \text{ ms}^{-2}$)

Binding energy per nucleon of deuteron and Helium nuclei are 1.1 MeV and 7 MeV respectively. If a single Helium nucleus was formed by adding two Deuterons, the energy released is

The potential difference between points A and B of adjoining figure is

Three balls $A$, $B$ and $C$ of equal mass are moving in the same order along the same straight line on a smooth horizontal surface. Initially, ball $A$ moves towards right with a velocity of $6\text{ ms}^{-1}$, ball $B$ moves towards left with a velocity of $4\text{ ms}^{-1}$ and ball $C$ moves towards right with a velocity of $3\text{ ms}^{-1}$. If the coefficient of restitution between any two balls is $0.8$, then the relative velocity of balls $B$ and $C$ after collision is

In the given circuit, the readings of voltmeters $V_{1}$ and $V_{2}$ are 300 V each. The reading of voltmeter $V_{3}$ and ammeter A are respectively

Two identical strings A and B of same material are having tensions $T_{A}$ and $T_{B}$ respectively. If their fundamental frequencies are 450 Hz and 300 Hz, then $T_{A}/T_{B}$ is

A wire carrying current I and other parallel wire carrying current 2I in the same direction produces a magnetic field B at the midpoint between them. Then the magnitude of field at the same point, when the 2I wire is switched off

Work function of a metallic surface is 5.01 eV. When a light of wavelength 2000Å falls on the metallic surface, it emits photo electrons. The potential difference required to stop the fastest photo electron is? (in Volt)

The atomic number (Z) of a hydrogen like atom whose shortest wavelength of Brackett Series is same as the shortest wavelength of Balmer series of hydrogen atom is

Cars $X$ and $Y$ begin the race simultaneously with velocities $8\text{ ms}^{-1}$ and $4\text{ ms}^{-1}$, moving in a straight line with uniform accelerations $2\text{ ms}^{-2}$ and $4\text{ ms}^{-2}$ respectively. If they reach final point at the same instant, then the length of the path is

$\beta=\frac{F}{v^{2}}\cos(\alpha t)$, if $F$ is force, $v$ is velocity, $t$ is time, then the dimensional formulae of $\alpha$, $\beta$ are respectively

A particle starting from the origin executes simple harmonic motion along x-axis. Its velocity at any instant t is given by $v_{x}=22 \cos(\frac{\pi t}{2}) \text{ cm s}^{-1}$. The total distance covered by the particle in time $t=4.5 \text{ sec}$ is

If $f_{m}$ is a modulating frequency and $f_{c}$ is carrier wave frequency, then Bandwidth in Amplitude Modulated wave is

A Carnot engine of 50 % efficiency takes heat from a source of 400 K. To change efficiency to 70 % without changing the sink temperature, the new temperature of source should be (nearer to)

A concave mirror is used to form an image of an object. The object distance (u) is 30 cm and the image distance (v) is 15 cm. Calculate the focal length (f) of the mirror.

A boy throws a ball into air at $45^\circ$ from the horizontal to land it on a roof of a building of height $H$. If the ball attains maximum height in $2\,\text{s}$ and lands on the building in $3\,\text{s}$ after launch, then the value of $H$ is ___ m.
(Given: $g = 10\,\text{m s}^{-2}$)

A closed tube filled with ideal gas is rotating with angular speed \(\omega\) about an axis passing through end \(A\). Find the pressure at the other end \(B\). (\(M\) is the molar mass of the gas, \(\ell\) is the length of the tube and \(T\) is the temperature of the gas.) Given pressure at \(A\) is \(P_A\).