List of top Physics Questions

According to Huygen's principle, during refraction of light from air to a denser medium

The ratio of wavelengths of the last line of Balmer series and the last line of Lyman series is :

A bicycle wheel rolls without slipping on a horizontal floor. Which one of the following is true about the motion of points on the rim of the wheel, relative to the axis at the wheel's centre?

A big water drop is formed by the combination of ?n? small water drops of equal radii. The ratio of the surface energy of ?n' drops to the surface energy of big drop is

Radii of two conducting circular loops are b and a respectively where b > > a. Centers of both loops coincide but planes of both loops are perpendicular to each other. The value of mutual inductance for these loops

The velocity of a particle executing a simple harmonic motion is $13\, ms^{-1}$, when its distance from the equilibrium position (Q) is 3 m and its velocity is $12 \, ms^{-1}$, when it is 5 m away from The frequency of the simple harmonic motion is

Two point charges $A = +3\, nC$ and $B = +1\, nC$ are placed $5\,cm$ apart in air. The work done to move charge $B$ towards $A$ by $1\,cm$ is

The bulk modulus of a spherical object is $'B'$. If it is subjected to uniform pressure $'p'$, the fractional decrease in radius is :

Photodiode is a device

The photoelectric threshold wavelength of silver is $3250 \times 10^{-10}m$. The velocity of the electron ejected from a silver surface by ultraviolet light of wavelength $2536 \times 10^{-10} m $ is (Given $ h = 4.14 \times 10^{-15} eVs$ and $c = 3 \times 10^8 \, ms^{-1}$)

The x and y coordinates of the particle at any time are $x = 5t - 2t^2$ and $y = 10t$ respectively, where $x$ and $y$ are in meters and t in seconds. The acceleration of the particle at $t = 2s$ is :

Suppose the charge of a proton and an electron differ slightly. One of them is $- e$, the other is ($e + \Delta e $). If the net of electrostatic force and gravitational force between two hydrogen atoms placed at a distance $d$ (much greater than atomic size) apart is zero, then $\Delta e$ is of the order of [Given mass of hydrogen $m_h = 1.67 \times 10^{-27} \, kg$]

The ratio of resolving powers of an optical microscope for two wavelengths $\lambda_1 = 4000 \mathring A$ and $\lambda_2 = 6000 \mathring A$ is :

Radioactive material $'A'$ has decay constant $' 8 \lambda '$ and material $'B' $ has decay constant $'\lambda'$ Initially they have same number of nuclei. After what time, the ration of number of nuclei of material of material $'B' $ to that $'A'$ will be $\frac{1}{e} ?$

Two Polaroids $P_1 $ and $P_2$ are placed with their axis perpendicular to each other. Unpolarised light $I_0$ is incident on $P_1$. A third polaroid $P_3$ is kept in between $P_1$ and $P_2$ such that is axis makes an angle 45$^{\circ}$ with that of $P_1$ .The intensity of transmitted light through $P_2$ is : -

Two discs of same moment of inertia rotating about their regular axis passing through centre and perpendicular to the plane of disc with angular velocities $\omega_1$ and $\omega_2$ . They are brought into contact face to face coinciding the axis of rotation. The expression for loss of energy during this process is:-

Which one of the following consumes least amount of electricity?

Preeti reached the metro station and found that the escalator was not working. She walked up the stationary escalator in time $t_1$. On other days, if she remains stationary on the moving escalator, then the escalator takes her up in time $t_2$. The time taken by her to walk up on the moving escalator will be

A rope of negligible mass is wound round a hollow cylinder of mass $3 \,kg$ and radius $40 \,cm$. If the rope is pulled with a force of $30 \,N$, then the angular acceleration produced in the cylinder is

The de-Broglie wavelength of a neutron in thermal equilibrium with heavy water at a temperature $T$ (Kelvin) and mass $m$, is :

A solid rectangular sheet has two different coefficients of linear expansion $\alpha_{1}$ and $\alpha_{2}$ along its length and breadth respectively. The coefficient of surface expansion is (for $\alpha_{1} t < < 1, \alpha_{2} t < < 1$)

The potential of an atom is given by \(V=Vo\ log_e (\frac {r}{r_o})\), where \(r_o\) is a constant and \(r\) is the radius of the orbit. Assuming Bohr's model to be applicable, which variation of \(r_n\) with \(n\) is possible (\(n\) being principal quantum number)?

You are given resistance wire of length 50 cm and a battery of negligible resistance. In which of the following cases is largest amount of heat generated?

The temperature of source and sink of a heat engine are 127°C and 27°C, respectively. An inventor claims its efficiency to be 26%, then