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

10^-6 M NaOH is diluted 100 times. The pH of the diluted base is

In the electrolysis of acidulated water, it is desired to obtain 1.12 cc of hydrogen per second under STP condition. The current to be passed is

The one which decreases with dilution is

Vapour pressure of pure ‘A’ is 70 mm of Hg at 25^oC. It forms an ideal solution with ‘B’ in which mole fraction of A is 0.8. if the vapour pressure of the solution is 84 mm of Hg at 25^oC, the vapour pressure of pure ‘B’ at 25^oC is

A 6% solution of urea is isotonic with

In countries nearer to polar region, the roads are sprinkled with CaCl₂. This is

A compound of ‘A’ and ‘B’ crystallises in a cubic lattice in which ‘A’ atoms occupy the lattice points at the corners of the cube. The ‘B’ atoms occupy the centre of each face of the cube. The probable empirical formula of the compound is

In electrophilic aromatic substitution reaction, the nitro group is meta directing because it

The best method for the conversion of an alcohol into an alkyl chloride is by treating the alcohol with

The carbon bond length in benzene is