The ratio of no. of turns of primary coil to secondary coil in a transformer is 1:2. If a cell of 1.5 V is connected across the primary coil, then e.m.f. across the secondary coil is
In hydrogen atom, if the difference in the energy of the electron in n = 2 and n = 3 orbits is E, the ionization energy of hydrogen atom is
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Two coils have a mutual inductance 0.005 H. The current cahnges in the first coil according to equation I=I₀ sin ωt where I₀ = 10 A and ω = 100π rad/sec. The maximum value of e.m.f. in second coil is
A mass of 2 kg is whirled in a horizontal circle by means of a string at an initial speed of 5 revolutions per minute. Keeping the radius constant the tension in the string is doubled. The new speed is nearly
A ball is allowed to fall from a height of 10 m. If there is 40% loss of energy due to impact, then after one impact ball will go up to
A galvanometer of 10 ohm resistance give full scale deflection with 0.01 ampere of current. It is to be converted into an ammeter for measuring 10 ampere current. The value of shunt resistance required will be
A photon of 1.7 x 10-13 Joules is absorbed by a material under special circumstances. The correct statement is
A wire suspended vertically from one of its ends is stretched by attaching a weight of 200 N to the lower end. The weight stretches the wire by 1 mm Then the elastic energy stores in the wire is
A Zener diode has a breakdown voltage of 9.1 V with a maximum power dissipation of 364 m W. What is the maximum current that the diode can withstand?
A charge q is placed at the centre of a cube. The magnitude of electric flux through one of its face will be
A box is lying on an inclined plane what is the coefficient of static friction if box starts sliding when an angle of inclination is 60o
There are two bodies of masses 100 kg and 10,000 kg separated by a distance 1 cm. At what distance from the smaller body, the intensity of gravitational field will be zero
A body cools in 7 minutes from 60oC to 40oC What time (in minutes) does it take to cool from 40oC to 28oC if the surrounding temperature is 10oC? Assume Newton's law of cooling.
A balloon contains 500 m2 of helium at 27oC and 1 atmosphere pressure. The volume of the helium at -3oC temprature and 0.5 atmosphere pressure will be
A 1 kg particle strikes a wall with velocity 1 m/s at an angle of 30o with the wall and reflects at the same angle. If it remains in contact with wall for 0.1 s, then the force is
A voltmeter of resistance 20000 Ω reads 5 volt. To make it read 20 volt, the extra resistance required is
A magnetic needle is kept in a non-uniform magnetic field. It experiences
A square plate of 0.1 m side moves parallel to another plate with a velocity of 0.1 m-s-1, both plates being immersed in viscous liquid. If the viscous force is 0.02 N and the coefficient of viscosity is 1 poise, then distance between the plates is
A ball is thrown up vertically with speed u. At the same instant another ball B is released from rest at height h. At time t, the speed of A relates to B is
If the equation for the displacement of a particle moving on a circular path is given by (θ) = 2t2 + 0.5, where θ is in radians and t in seconds, then the angular velocity of the particle after 2 sec from its start is
A rocket is propelled by a gas which is initially at a temperature of 4000 K. The temperature of the gas falls to 1000 K as it leaves the exhaust nozzle. The gas which will acquire the largest momentum while leaving the nozzle, is
A particle is viberating in a simple harmonic motion with an amplitude of 4 cm. At what displacement from the equilibrium position, is its energy half potential and kinetic ?
A projectile is fired at 30o, momentum p. Neglecting friction, the change in kinetic energy when it returns to the ground will be
The coefficient of viscosity of a gas is:
1. Directly proportional to the mass of the gas molecule
2. Directly proportional to the average velocity of the gas molecule
3. Inversely proportional to the square of the diameter of the molecule
Which of the above statements are correct?
The image formed by an objective of a compound microscope is
A solid cylinder of mass M and radius R rolls down an inclined plane without slipping. The speed of its centre of mass when it reaches the bottom is
A current i passes through a wire of length l, radius of cross-section r and density ρ. The rate of heat generation is
Density of a substance at 0oC is 10gm/c.c and at 100oC its density is 9.7gm/c.c. The coefficient of linear expansion of the substance is