List of top Physics Questions

The power dissipated by a uniform wire of resistance $100~\Omega$ when a potential difference of $120~\text{V$ is applied across its ends is}

The radii of inner and outer spheres of a spherical capacitor are $8~\text{cm$ and $9~\text{cm}$ respectively. The outer sphere is earthed and the inner sphere is charged. If the space is filled with a dielectric constant $K = 5$, the capacitance is}

Three particles of each charge $q$ are placed at the vertices of an equilateral triangle of side $L$. The work to be done to decrease the side of the triangle to $\dfrac{L{2}$ is}

If 27 charged water droplets, each of radius $10^{-6~\text{m}$ and charge $10^{-12}~\text{C}$ coalesce to form a single spherical drop, then the potential of the big drop is}

If a straight current-carrying wire of linear density $0.12~\text{kg/m$ is suspended in mid-air by a uniform horizontal magnetic field of $0.5~\text{T}$ normal to the length of the wire, then the current through the wire is (Neglect earth’s magnetic field)}

Two concentric loops $A$ and $B$ of same radius $2\pi~\text{cm$ are placed at right angles to each other. If the currents flowing through $A$ and $B$ are $3~\text{A}$ and $4~\text{A}$ respectively, then the net magnetic field at their common center is}

For an observer on the earth, if a spectral line of wavelength $6600~\mathring{A$ emitted by a star is found to be redshifted by $22~\mathring{A}$, then the star is}

If a gas of volume $400~\text{cc$ at an initial pressure $P$ is suddenly compressed to $100~\text{cc}$, then its final pressure is (The ratio of specific heats $\gamma = 1.5$)}

A Carnot engine having efficiency $60%$ receives heat from a source at temperature $600~\text{K$. For the same sink temperature, to increase its efficiency to $80%$, the temperature of the source is}

The average translational kinetic energy of oxygen molecules at a temperature of $127^\circ\text{C$ is (Boltzmann constant $= 1.38 \times 10^{-23}~\text{J/K}$)}

Two thin convex lenses are kept in contact coaxially. If the focal length of the combination is $4~\text{cm$ and the sum of the focal lengths of the two lenses is $18~\text{cm}$, then the focal length of the lens of low power is}

The kinetic energy of a particle executing simple harmonic motion at a displacement of $3~\text{cm$ from the mean position is $4~\text{mJ}$. If the amplitude of the particle is $5~\text{cm}$, then the maximum force acting on the particle is}

Two bodies of masses $2~\text{kg}$ and $3~\text{kg}$ move at right angles with velocities $20~\text{m/s}$ and $10~\text{m/s}$ respectively.
Then the velocity of the centre of mass of the system is

A body of mass $1~\text{kg$ is attached to the lower end of a vertically suspended spring of force constant $600~\text{N/m}$. If another body of mass $0.5~\text{kg}$ moving vertically upward hits the suspended body with a velocity $3~\text{m/s}$ and is embedded in it, then the frequency of the oscillation is}

A car is moving with a velocity of $4~\text{m/s}$ towards east. After a time of $4~\text{s}$, it is heading north-east with a velocity of $4\sqrt{2}~\text{m/s}$. Then the average velocity of the car is

A steel sphere of radius $1.2~\text{cm}$ collides with another steel sphere at rest.
If the collision is elastic and the first sphere moves with $\dfrac{7}{9}$ of its initial velocity after collision,
then the radius of the second sphere is

Ratio of angular velocity of hour hand of a watch and the angular velocity of rotation of earth is

The bob of a simple pendulum of length $200~\text{cm}$ is released from horizontal position.
If $10%$ of its initial energy is lost to air resistance, then the speed of bob at the mean position is
(Acceleration due to gravity $= 10~\text{m/s}^2$)

A block of mass $10~\text{kg}$ moving with a speed of $5~\text{m/s}$ on a frictionless horizontal surface suddenly explodes into two pieces.
If one piece with mass $4~\text{kg}$ moves with a speed of $10~\text{m/s}$, then the velocity of the second piece is