List of top Physics Questions

In Young's double slit experiment 10th order maximum is obtained at the point of observation in the interference pattern for \( \lambda = 7000 \, \text{Å} \). If the source is replaced by another one of wavelength 5000 Å then the order of maximum at the same point will be –

When light is refracted, which of the following does not change?

Which of the following electromagnetic radiations has the smallest wavelength?

Eddy currents are produced when

Two coaxial solenoids are made by winding thin insulated wire over a pipe of cross-sectional area \( A = 10 \, \text{cm}^2 \) and length 20 cm. If one of the solenoids has 300 turns and the other 400 turns, their mutual inductance is

The ratio of secondary and primary turns of step-up transformer is 4 : 1. If a current of 4 A is applied to the primary, the induced current in secondary will be

A uniform electric field and uniform magnetic field are acting along the same direction in a certain region. If an electron is projected in the region such that its velocity is pointed along the direction of fields, then the electron

What should be the characteristic of fuse wire?

Two parallel conductors carry current in opposite directions as shown in figure. One conductor carries a current of 10.0 A. Point C is a distance \( \frac{d}{2} \) to the right of the 10.0 A current. If \( d = 18 \, \text{cm} \) and \( I \) is adjusted so that the magnetic field at C is zero, the value of the current \( I \) is
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Two identical capacitors, have the same capacitance \( C \). One of them is charged to potential \( V_1 \) and the other to \( V_2 \). The negative ends of the capacitors are connected together. When the positive ends are also connected, the decrease in energy of the combined system is –

Three equal charges (\( q \)) are placed at corners of an equilateral triangle of side \( a \). The force on any charge is –

Two waves of wavelengths 99 cm and 100 cm both travelling with velocity 396 m/s are made to interfere. The number of beats produced by them is

If the equation of transverse wave is \( y = x_0 \cos \left( 2\pi \left( nt - \frac{x}{\lambda} \right) \right) \), the maximum velocity of the particle is twice of wave velocity, if \( k \) is –

Two gases occupy two containers A and B. The gas in A, of volume 0.10 m³, exerts a pressure of 1.40 MPa and that in B of volume 0.15 m³ exerts a pressure of 0.7 MPa. The two containers are united by a tube of negligible volume and the gases are allowed to intermingle. Then if the temperature remains constant, the final pressure in the container will be (in MPa)

An instantaneous displacement of a simple harmonic oscillator is \( x = A \cos(\omega t + \pi/4) \). Its speed will be maximum at time

A vessel containing 1 more of \( O_2 \) gas (molar mass 32) at temperature \( T \). The pressure of the gas is \( p \). An identical vessel containing one mole of He gas (molar mass 4) at temperature 2T has a pressure of –

The temperature of an ideal gas is increased from 27°C to 127°C, then the percentage increase in \( v_{\text{rms}} \) is

A Carnot's heat engine works between the temperatures 427°C and 27°C. What amount of heat should it consume per second to deliver mechanical work at the rate of 1.0 kW?

A thermodynamic system is changed from state \( (P_1, V_1) \) to \( (P_2, V_2) \) by two different processes, the quantity which will remain same will be –

A ball whose density is \( 0.4 \times 10^3 \, \text{kg/m}^3 \) falls into water from a height of 9 cm. To what depth does the ball sink?

If the radius of a star is \( R \) and it acts as a black body, what would be the temperature of the star, in which the rate of energy production is \( Q \)?

A particle of mass \( m \) is projected with a velocity \( v \) making an angle of \( 30^\circ \) with the horizontal. The magnitude of angular momentum of the projectile about the point of projection when the particle is at its maximum height \( h \) is –

A block of mass \( m \) is placed on a smooth inclined wedge ABC of inclination \( \theta \) as shown in the figure. The wedge is given an acceleration \( a \) towards the right. The relation between \( a \) and \( g \) for the block to remain stationary on the wedge is
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A 3.628 kg freight car moving along a horizontal rail road spur track at 7.2 km/hour strikes a bumper whose coil springs experiences a maximum compression of 30 cm in stopping the car. The elastic potential energy of the springs at the instant when they are compressed 15 cm is –

A body is projected, making an acute angle \( \theta \) with the horizontal. If angle between velocity \( \vec{v} \) and acceleration \( \vec{g} \) is \( \theta \), then