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The first line of Balmer series has wavelength 6563 Å. What will be the wavelength of the first member of Lyman series
n identical cells each of e.m.f. E and internal resistance r are connected in series. An external resistance R is connected in series to this combination. The current through R is
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
The electrical conductivity of the earth's atmosphere increases with altitude due to
A satellite which is geostationary in a particular orbit is taken to another orbit. Its distance from the centre of earth in new orbit is 2 times that of the earlier orbit. The time period in the second orbit is
A body takes 1 1/3 times as much time to slide down a rough inclined plane as it takes to slide down an identical but smooth inclined plane. If the angle of inclination of the inclined plane is 45^{o}, the coefficient of friction is
If a liquid is heated in weightlessness, the heat is transmitted through
A straight wire of diameter 0.5 mm carrying a current of 1 A is replaced by another wire of 1 mm diameter carrying the same current. The strength of magnetic field far away is
A square plate of 0.1 m side moves parallel to another plate with a velocity of 0.1 ms⁻^{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
Which of the following instruments is used to measure magnetic field ?
Raindrops are falling from a certain height. Assume all raindrops are spherical and have same drag coefficient. The impact speed of large raindrops compared to that of small raindrops is
A uniform plank of Young's modulus Y, is moved over a smooth horizontal surface by a constant horizontal force F. The area of crosssection of plank is A. The compressive strain on the plank in the direction of the force is
Two quantities A and B have different dimensions. Which of the following operation is correct?
A ball is dropped downwards. After 1 second another ball is dropped downwards from the same point. What is the distance between them after 3 seconds
A bullet is fired from a gun with a velocity of 1000 m−s⁻^{1} in order to hit a target 100 m away. At what height above the target should the gun be aimed? (Resistance of air is negligible and g = 10 m−s⁻^{2})
If the tension in the cable of 1000 kg elevator is 1000 kg weight, the elevator
If a solid spherical ball is rolling on a horizontal table, the ratio of its rotational kinetic energy to the total energy is
A train is moving with a constant velocity.If a pendulum is hanging from its roof, then its time period will
If a simple pendulum oscillates with an amplitude 50 mm and time period of 2 s, then its maximum velocity, is
Three rods each of length L and mass M are placed along X, Y and Z axes in such a way that one end of each of the rod is at the origin. The moment of inertia of this system about Z axis is
A boy stands over the centre of a horizontal platform which is rotating freely with a speed of 2 revolutions/sec about a vertical axis through the centre of the platform and straight up through the boy. He holds 2 kg masses in each of his hands close to his body. The combined moment of inertia of the systam is 1 kg*metre^{2}. The boy now stretches his arms so as to hold the masses far from his body. In this situation the moment of inertia of the system increases to 2 kg*metre^{2}. The kinetic energy of the system in the latter case as compared with that in the previous case will
When a current is passed through a junction of two dissimilar metals, heat is evolved or absorbed at the junction. This process is called
A scientists says that the efficiency of his heat engine which works at source temperature 127^{o}C and sink temperature 27^{o}C, is 26%
A mountain climber finds that water boils at 80^{o}C. The temperature of this boiling water on Fahrenheit scale is
If the measurement of a length is made as (2271) mm, then percentage error in the measurement is
Bright colours exihibited by spider's web exposed to sun light are due to
In young's double slit experiment, three light, blue, yellow and red are used successively. For which colour, will the fringe width be maximum?
The equation y = A cos^{2}(2π nt  2π x/λ) represents a wave with
The ratio of intensities of two waves is 9:1. When they superimpose, the ratio of maximum to minimum intensities will become
Water falls from a height of 60 m at the rate of 15 kg/s to operate a turbine . The losses due to frictional forces are 10% of energy . How much power is generated by the turbine ?(g = 10 m/s^{2})
A force of 10 N displaces an object by 10 m. If work done is 50 J, then direction of force makes an angle with direction of displacement
2 videos14 docs143 tests

2 videos14 docs143 tests
