In ruby laser, the stimulated emission is due to transition from

A direct current I flows along the length of an infinitely long straight thin walled pipe, then the magnetic field is

convex lens made of glass has focal length 0.15m in air. If the refractive index of glass is 3/2, and that of water is 4/3 the focal length of lens when immersed in water is

Two sources are said to be coherent if they produce waves

Three resistors 1 Ω, 2 Ω, 3Ω resistor a 3 V battery is connected. The current through 3 Ω resistor is -

In a common emitter amplifier the input signal is applied across

Adding detergents to water helps in removing dirty greasy stains. This is because
1. It increases greasy stains. This is because
2. It decreases the oil-water surface tension
3. It increases the viscosity of the solution
4. Dirt is held suspended surrounded by detergent molecules

Choose the correct statement (a) for a cricket ball that is spinning clockwise through air
S1 : Statemlines of air are symmetric around the ball.
S2 : The velocity of air above the ball relative to it is larger than that below the ball.
S3 : The velocity of air above the ball relative to it is smaller than that below the ball.
S4 : There is a net upward force on the ball.

Ferromagnetic materials used in a transformer must have

According to Newton’s corpuscular theory, the speed of light is

For the constructive interference the path difference between the two interfering waves must be equal to

The accurate measurement of emf can be obtained using

A person, with outstretched arms, is spinning on a rotating stool. He suddenly brings his arms down to his sides. Which the following is true about his kinetic energy K and angular momentum L?

Which of the following is not a thermodynamic coordinate?

An antenna uses electromagnetic waves of frequency 5 MHz . For proper working, the size of the antenna should be

The amount of energy released when one microgram of matter is annihilated is

The number of significant figures in the numbers 4.8000 x 10⁴ 48000.50 are respectively

β-decay means emission of electron from

An electric heater rated 220 V and 550 W is connected to AC mains. The current drawn by it is

A string is wound round the rim of a mounted flywheel of mass 20 kg and radius 20 cm. A steady pull of 25 N is applied on the cord. Neglecting friction and mass of the string, the angular acceleration of the wheel is

A billiards player hits a stationary ball by an identical ball to pocker the target ball in a corner pocket that is at an angle of 35^o with respect to the direction of motion of the first ball. Assuming the collision as elastic and that frictional and rotational motions are not important, the angle made by the target ball with respect to the imcoming ball is

A body of mass 0.05 kg is observed to fall with an acceleration of 9.5 ms^-2. The opposing force of air on the body is (g = 9.8 ms^-2)

The colloidal solution in which both the dispersed phase and dispersion medium are liquids are called

In fog, photographs of the objects taken with infrared radiations are more clear than those obtained during visible light because

Three concurrent co-planar forces 1 N, 2 N and 3 N acting along different directions on a body

Sound waves transfer

G P Thomson experimentally confirmed the existence of matter waves by the phenomena

The resistance of a wire at 300 K is found to be 0.3 Ω. If the temperature coefficient of resistance of wire is 1.5 x 10^-3 K^-1, the temperature at which the resistance becomes 0.6 Ω is

Two luminous points sources separated by a certain distance are at 10 km from an observer. If the aperture of his eye is 2.5 x 10^-3 m and the wavelength of light used is 500 nm the distance of separation between the point sources just seen to be resolved is

A door 1.6 m wide requires a force of N to be applied at the free end to open or close it. The force that is required at a point 0.4 m distance from the hinges for opening or closing the door is

0.1 m³ of water at 80^o C. The final temperature of the mixture is

The spectral series of the hydrogen atom that lies in the visible region of the electromagnetic spectrum

A resistor and a capacitor are connected inseries  with an AC source. If the potential drop across the capacitor is 5 V and that across resistor is 12 V, then applied voltage is

The amount of heat energy radiated by a metal at temperature T is E. When the temperature is increased to 3T, energy radiated is

A man, of mass 60 kg, is riding in a lift. The weights of the man, when the lift is accelerating upwards and down wards at 2m/s² are respectively (Taking g=2m/s²)

A galvanometer of resistance 240 Ω allows only 4% of the main current after connecting a shunt resistance. The value of the shunt resistance is

The phenomena in which proton flips is

According to the quark model, it is possible to build all the hadrons using

The surface temperature of the stars is determined using

A parallel beam of light is incident on a converging lens parallel to its principal axis. As one moves away from the lens on the other side of the principal axis, the intensity of light

Continuous emission spectrum is produced by

A ray of light is incident on a plane mirror at an angle of 60⁰. The angle of deviation produced by the mirror is

The electric potential at any point x,y,z in metres is given by V = 3x². The electric field at point (2,0,1) is

Young’s double. Slit experiment gives interference fringes of width 0.3 mm. A thin glass plate made of material of refractive index 1.5 is kept in the path of light from one of the slits, then the fringe width becomes

The magnetic dipole moment of a current loop is independent of

2 g of a radioactive sample having half-life of 15 days was synthesised on 1^st Jan 2009. The amount (including both the days) is

The ratios of the distance traversed, in successive intervals of time by a body, falling from rest, are

A source having frequency of 240 Hz is moving towards on observer with a speed of 20 m/s. when the observer is moving towards the source with a velocity of 20m/s. then apparent frequency heard by the observer, if velocity of sound is 330m/s, will be:

Choose the incorrect statement out of the following.

If E,M,L and G denote energy, mass, angular momentum and gravitational constant respectively then the quantity ( E²L²/M⁵G²) has the dimensions of

Which of the following does not depict the correct link between technology and physics?

If the velocity of sound in air is 336 m/s. The maximum length of a closed pipe that would produce a just audible sound will be

Which of the following statements is true, when spherical waves fall on a plane refracting surface, separation two media?

The speed of electromagnetic wave in vacuum depends upon the source of radiation

Two coherent monochromatic light beams of intensities I and 4I are superposed. The maximum and minimum possible resulting intensities are

If the radius of earth is reduced by 2% keeping its mass constant. Then the weight of the body on its surface will

A beam of light of wavelength 600 nm from a distant source falls on a single slit 1 mm wide and the resulting diffraction pattern is observed on a screen 2 m away. The distance between the first dark fringes on either side of the central bright fringe is

In an astronomial telescope, the focal length of objective lens and eye piece are 150 cm and 6 cm respectively. In normal adjustment the magnifying power is

In an experiment with Kund’s tube, the distance between consecutive nodes is 5 cm, when air is inside and it is 13.4 cm, when hydrogen is inside then the velocity of sound in hydrogen will be (velocity of sound in air = 330 m/s) :

An element A decays into an element C by a two step process.
A → B + 2He4
B → C + 2e-
Then

Which of the following is the infrared wavelength?

Chromatic aberration of lens can be corrected by

The forward voltage in a diode increased the width of the depletion region:

Time-period of a pendulum on a satellite, orbiting around the earth, is

The current in a coil of inductance 0.2 H changes from 5 A to 2 A in 0.5 sec . The magnitude of the average induced emf in the coil is

A charged hollow sphere does not produce an electric field at any

An astronaut on a strange planet finds that acceleration due to gravity is twice as that on the surface of earth. Which of the following could explain this?

A small object is placed 10 cm in front of a plane mirror. If you stand behind the object 30 cm from the mirror and look at its image, the distance foccused for your eye will be:

Three polaroid sheets P₁, P₂ and P₃ are kept parallel to each other such that the angle between pass axes of P₁and P₂ is 45⁰ and that between P₂ and P₃ is 45⁰ . If unpolarised beam of light of intensity 128 Wm^-2 is incident on P₁ . What is the intensity of light coming out of P₃ ?

While a capacitor remains connected to a battery and dielectric slab is applied between the plates, then:

There are two electric bulbs of 40 volt and 60 volt. The ratio of their resistance will be:

A beam of light in air enters into the water. Which of the following characteristics of light will not change?

If a ball is thrown vertically upwards, assuming the air resistance to be constant and considerable, then :

The work function for aluminium is 4.125 eV. The cutoff wavelength for photoelectric effect for aluminium will be:

A bus is moving with a velocity of 5 m/s towards a huge well. The driver sounds a horn of frequency 165 Hz. If the speed of sound in air is 355 m/s, the number of beats heard per second by a passenger on the bus will be:

If the critical angle for total internal reflection from a medium to vacuume is 30⁰ then velocity of light in the medium is:

In a stationary wave all particles of the medium cross the mean position with:

A cylinder of 5 litre capacity, filled with air at N.T.P. is connected with another evacuated cylinder of 30 litres of capacity the resultant air pressure in both the cylinders will be :

As the intensity of incident light increases then:

Pick out the statement which is not true:

What happens, when we multiply a vector by –2 ?

A train is moving towards north with a speed of 180 km/hr. If the vertical component of the earth’s magnetic field is 0.2 × 10^-4 T, e.m.f. induced, in the axle 1.5 m long, is:

When a ceiling fan is switched off its angular velocity radius 50% while its makes 36 rotations. How many more rotation will it make before coming to rest (assume uniform angular retardation ) :

At sea level, the value of g is minimum at 

When there are no external forces, the shape of a small liquid drop is determined by

A gas at the temperature 250 K is contained in a closed vessel. If the gas is heated through 1 K, then the percentage increase in its pressure will be:

Whenever stationary waves are set up, in any medium, then

A block of mass 1kg slides down a rough inclined plane of inclination 60⁰ starting from its top. If coefficient of kinetic friction is 0.5 and length of the plane d=1 m then work done against friction is:

A bar magnet of magnetic moment M is cut into two parts of equal length. The magnetic moment of each part will be

A body thrown upwards with some velocity, reaches the maximum height of 20 m. Another body with double the mass thrown up, with double initial velocity will reach a maximum height of:

A particle having charge 100 times that of an electron is revolving in a circular path of radius 0.8 m with one rotation per second. Magnetic field produced at the centre of particle will be:

There is a uniform magnetic field directed perpendicular and into the plane of the paper. An irregular shaped conducting loop is slowly changing into a circular loop in the plane of the paper. Then 

The energy of hydrogen atom in its ground state is -13.6 eV. The energy of the level corresponding to the quantum number n is equal 5 is:

Water is in streamline flows along a horizontal pipe with non-uniform cross-section. At a point in the pipe where the area of cross-section is 10 cm², the velocity of water is 1 ms^-1 and the pressure is
2000 Pa. The pressure at another point where the cross-sectional area is 5 cm² is

Magnetic fields at two points on the axis of a circular coil at a distance of 0.05 m and 0.2 m from the centre are in the ratio 8 : 1 The radius of the coil is:

A balloon starts rising from the ground with an acceleration of 1.25 m/s² after 8s, a stone is released from the balloon. The store will (g = 10 m/s²):

If a while light is used in Young’s double slit experiments then a very large number of coloured fringes can be seen: