List of top Physics Questions

A block of mass 1 kg is pushed up a surface inclined to horizontal at an angle of 60° by a force of 10 N parallel to the inclined surface as shown in the figure. When the block is pushed up by 10 m along the inclined surface, the work done against frictional force is:

Two charges \(Q\) and \(3Q\) are kept in a line separated by a distance \(R\). Electric field is zero at a distance x from \(Q\). Find the value of \(x\).

Stopping potential is \(8\) \(V\) if wavelength of incident light is \(λ\) and it is \(2\) \(V\) for \(3λ\). Find threshold wavelength.

Two particles are projected from a tower of height 400 m & angles 45° & 60° horizontally. If they have the same time of flight, find the ratio of their velocities.

An electric toaster has resistance of \( 60 \, \Omega \) at room temperature \( (27^\circ \text{C}) \). The toaster is connected to a 220 V supply. If the current flowing through it reaches 2.75 A, the temperature attained by the toaster is around: (if \( \alpha = 2 \times 10^{-4} / ^\circ \text{C} \))

The gravitational potential at a point above the surface of earth is \( -5.12 \times 10^7 \, \text{J} / \text{kg} \) and the acceleration due to gravity at that point is \( 6.4 \, \text{m/s}^2 \). Assume that the mean radius of earth to be \( 6400 \, \text{km} \). The height of this point above the earth’s surface is:

In \(AC\) circuit with source voltage \(E \) = \(20\) \(sin\; 1000 \;t\) is connected to series \(L-R\) circuit whose power factor is \(\frac{1}{\sqrt 2}\) If \(E = 25\) \(sin \;2000\) \(t\), the new power factor is :

At which temperature the r.m.s. velocity of a hydrogen molecule equal to that of an oxygen molecule at 47ºC?

Primary coil of a transformer is connected to 220 V ac. Primary and secondary turns of the transforms are 100 and 10 respectively. Secondary coil of transformer is connected to two series resistance shown in shown in figure. The output voltage (V0) is :

If the area of cross-section is halved and length of a wire having Young's modulus Y is doubled, then its new Young's modulus will be

The electric field in an electromagnetic wave is moving in a free space given as vec \(E =E_ 0 \;sin(⍵t - kz)\) \(i\) The corresponding magnetic field will be:

A long wire carrying current \(\sqrt{(2)}A\) is placed in a uniform magnetic field of \(3 \times 10^{-5}\; T\). If the magnetic field is perpendicular to wire, find magnetic force on the length of wire.

The work function of a substance is 3.0 eV. The longest wavelength of light that can cause the emission of photoelectrons from this substance is approximately:

A uniform disc of mass \(5\) \(kg\) and radius \(2\) \(m\) is rotating with \(10\) \(rad/s\). Now another identical disc is gently placed on first disc. Because of friction both disc acquire common angular velocity. Loss of kinetic energy in process is ________J.

A particle is having uniform acceleration. If its displacement from t to \((t + 1)\) second is \(120 \) \(m\) and change in velocity is \(50 \;m/s\). Find its displacement (in m) in \((t + 2)^{th}\) second

Distance between virtual image, which is twice the size of object placed in front of mirror and object is 45 cm. The magnitude of focal length of the mirror is _____cm.

A block of mass \(2\) \(kg\) is placed on a disc which is rotating at constant angular velocity \(4\) \(rad/sec\). Find the friction force in (N) between block and disc if block is not sliding.

The electrostatic potential due to an electric dipole at a distance \( r \) varies as:

Find the current through Zener diode if its breakdown voltage is 5 V.

A ball is released from a height of \(1\) \(m\) on a fixed smooth hemispherical surface as shown. Find its velocity when it is at a height of \(0.5\) \(m\) from ground. (take \(g\) = \(10\;m / s^2\))

Find the potential difference across \(700\) \(Ω\) resistance (i.e. Vo)

A particle of mass m is projected from ground with speed u at an angle of 30° with the horizontal. Find its angular momentum about the point of projection when it reaches its maximum height.

Find the acceleration of \(2\) \(kg\) block shown in the diagram (neglect friction)

Two rings of equal radius \(R\) arranged perpendicular to each other with common center at \(C\), carrying equal current \(I\). Find magnetic field at \(C\).