List of top Physics Questions

The kinetic energy of electron and photon arc the same. The relation between their De - Broglie wavelengths $ \lambda _e $ and $ \lambda _p $ is
A solid cylinder of mass $ M $ and radius $ R $ rolls on a flat surface. Find its moment of inertia about the line of contact.
An extrinsic semiconductor with electrons as majority carriers can be obtained by doping $ Ge $ or $ Si $ with
The difference between the maximum and minimum values of resistance of a resistor with the color scheme green-green-red-silver is
Which of the following is the indirect way of generating $ FM $ ?
A physical quantity X is given by $X=\frac{2k^{3}l^{2}}{m\sqrt{n}}$ The percentage error in the measurements of k, l, m and n are 1%, 2%, 3% and 4% respectively. The value of X is uncertain by
The magnetic field due to a current in a straight wire segment of length $L$ at a point on its perpendicular bisector at a distance $r (r >> L)$
A lift of mass $m$ is connected to a rope which is moving upward with maximum acceleration $a$. For maximum safe stress, the elastic limit of the rope, is $T$. The minimum diameter of the rope is (g = gravitational acceleration)
A metal rod of length ????and cross-sectional area ????is heated through $???? \, {^{\circ}C}$. What is the force required to prevent the expansion of the rod lengthwise ? [Y = Young's modulus of the material of rod , $\alpha$ = coefficient of linear expansion]
The resistance of a wire is ‘R’ ohm. If it is melted and stretched to ‘n’ times its original length, its new resistance will be
The two nearest harmonics of a tube closed at one end and open at other end are 220 Hz and 260 Hz. What is the fundamental frequency of the system?
A rope is wound around a hollow cylinder of mass 3 kg and radius 40 cm. What is the angular acceleration of the cylinder if the rope is pulled with a force of 30 N?
A beam of light from a source L is incident normally on a plane mirror fixed at a certain distance x from the source. The beam is reflected back as a spot on a scale placed just above the source L. When the mirror is rotated through a small angle θ, the spot of the light is found to move through a distance y on the scale. The angle θ is given by
A thin prism having refracting angle 10° is made of glass of refractive index 1.42. This prism is combined with another thin prism of glass of refractive index 1.7. This combination produces dispersion without deviation. The refracting angle of second prism should be
Preeti reached the metro station and found that the escalator was not working. She walked up the stationary escalator in time t1. On other days, if she remains stationary on the moving escalator, then the escalator takes her up in time t2. The time taken by her to walk up on the moving escalator will be
A spherical black body with a radius of 12 cm radiates 450 watt power at 500 K. If the radius were halved and the temperature doubled, the power radiated in watt would be
Two blocks A and B of masses 3m and m respectively are connected by a massless and inextensible string. The whole system is suspended by a massless spring as shown in figure. The magnitudes of acceleration of A and B immediately after the string is cut, are respectively
wo blocks A and B of masses 3m and m respectively are connected by a massless
A long solenoid of diameter 0.1 m has 2 × 104 turns per meter. At the centre of the solenoid, a coil of 100 turns and radius 0.01 m is placed with its axis coinciding with the solenoid axis. The current in the solenoid reduces at a constant rate to 0 A from 4 A in 0.05 s. If the resistance of the coil is 10π2 Ω, the total charge flowing through the coil during this time is
Two Polaroids P1 and P2 are placed with their axis perpendicular to each other. Unpolarised light l0 is incident on P1. A third polaroid P3 is kept in between P1 and P2 such that its axis makes an angle 45º with that of P1. The intensity of transmitted light through P2 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 ω1 and ω2. They are brought into contact face to face coinciding the axis of rotation. The expression for loss of energy during this process is
Two astronauts are floating in gravitational free space after having lost contact with their spaceship. The two will:
An arrangement of three parallel straight wires placed perpendicular to plane of paper carrying same current ‘I’ along the same direction is shown in Fig. Magnitude of force per unit length on the middle wire ‘B’ is given by
An arrangement of three parallel straight wires placed perpendicular to plane
In an electromagnetic wave in free space the root mean square value of the electric field is Erms = 6 V/m. The peak value of the magnetic field is
If θ1 and θ2 be the apparent angles of dip observed in two vertical planes at right angles to each other, then the true angle of dip θ is given by
The ratio of resolving powers of an optical microscope for two wavelengths λ1 = 4000 Å and λ2 = 6000 Å is