List of top Physics Questions

A capacitor of capacitance \( C \) and potential \( V \) has energy \( E \). It is connected to another capacitor of capacitance \( 2C \) and potential \( 2V \). Then the loss of energy is \( \frac{x}{3} E \), where \( x \) is \( \_\_\_\_ \).

If \( S_1 \), \( S_2 \), and \( S_3 \) are the tensions at liquid-air, solid-air and solid-liquid interfaces respectively, and \( \theta \) is the angle of contact at the solid-liquid interface, then

If the peak value of the magnetic field of an electromagnetic wave is \( 30 \times 10^{-9} \, \text{T} \), then the peak value of the electric field is

An electric dipole of dipole moment \( \vec{p} \) is kept in a uniform electric field \( \vec{E} \). The amount of work done to rotate it from the position of stable equilibrium to that of unstable equilibrium will be:

A planet at distance r from the sun takes 200 days to complete one revolution around the sun. What will be the time period for a planet at distance \(\frac{r}{4}\) from the sun?

Five charges, 'q' each are placed at the corners of a regular pentagon of side 'a' as shown in figure. First, charge from 'A' is removed with other charges intact, then charge at 'A' is replaced with an equal opposite charge. The ratio of magnitudes of electric fields at O, without charge at A and that with equal and opposite charge at A is

Four identical particles each of mass 'm' are kept at the four corners of a square of side 'a'. If one of the particles is removed, the shift in the position of the centre of mass is:

The property which is not of an electromagnetic wave travelling in free space is that :

For a gas in a thermodynamic process, the relation between internal energy (U), the pressure (P), and the volume (V) is given by: \[ U = 3 + 1.5PV \] The ratio of the specific heat capacities of the gas at constant volume and constant pressure is:

A small-angled prism is made of a material of refractive index \( \frac{3}{2} \). The ratio of the angles of minimum deviations when the prism is placed in air and in water of refractive index \( \frac{4}{3} \) is:

When \( Q \) amount of heat is supplied to a monatomic gas, the work done by the gas is \( W \). When \( Q_1 \) amount of heat is supplied to a diatomic gas, the work done by the gas is \( 2W \). Then \( Q:Q_1 \) is:

A boy standing on a platform observes the frequency of a train horn as it passes by. The change in the frequency noticed as the train approaches and recedes from him with a velocity of 108 km/h (speed of sound in air = 330 m/s) is:

A small telescope has an objective of focal length 140 cm and an eye piece of focal length 5.0 cm. The magnifying power of telescope for viewing a distant object is :

A block of mass 2 kg is tied to one end of a 2 m long metal wire of 1.0 mmÂ² area of cross-section and rotated in a vertical circle such that the tension in the wire is zero at the highest point. If the maximum elongation in the wire is 2 mm, the Young's modulus of the metal is:

A force is represented by \( F = ax^2 + b t^{1/2} \) Where \( x = \) distance and \( t = \) time. The dimensions of \( \frac{b^2}{a} \) are:

A particle moving with uniform speed in a circular path maintains :

A thermodynamic system is taken through the cycle abcda. The work done by the gas along the path bc is :

Match List I with List II.

List I (Spectral Lines of Hydrogen for transitions from)		List II (Wavelength (nm))
A.	n₂ = 3 to n₁ = 2	I.	410.2
B.	n₂ = 4 to n₁ = 2	II.	434.1
C.	n₂ = 5 to n₁ = 2	III.	656.3
D.	n₂ = 6 to n₁ = 2	IV.	486.1

Choose the correct answer from the options given below:

37 g of ice at 0Â°C is mixed with 74 g of water at 70Â°C. The resultant temperature is:

A body thrown vertically upwards from the ground reaches a maximum height ‘h’. The ratio of the kinetic and potential energies of the body at a height 40\% of h from the ground is

In a uniform magnetic field of \(0.049 T\), a magnetic needle performs \(20\) complete oscillations in \(5\) seconds as shown. The moment of inertia of the needle is \(9.8 \times 10 kg m^2\). If the magnitude of magnetic moment of the needle is \(x \times 10^{-5} Am^2\); then the value of '\(x\)' is

A conductor of length 1.5 m and area of cross-section \( 3 \times 10^{-5} \, \text{m}^2 \) has electrical resistance of 15 \( \Omega \). The current density in the conductor for an electric field of 21 \( \text{V/m} \) is.

The temperature at which the rms speed of oxygen molecules is 75\% of the rms speed of nitrogen molecules at a temperature of \( 287^\circ C \) is:

A metal target with atomic number \( Z = 46 \) is bombarded with a high-energy electron beam. The emission of X-rays from the target is analyzed. The ratio \( r \) of the wavelengths of the \( K_\alpha \)-line and the cutoff is found to be \( r = 2 \). If the same electron beam bombards another metal target with \( Z = 41 \), the value of \( r \) will be:

An object is placed at a distance of 18 cm in front of a mirror. If the image is formed at a distance of 4 cm on the other side, then the focal length, nature of the mirror and nature of the image are respectively: