In order to obtain a time constant of 10 seconds in an RC circuit containing a resistance of 103Ω, the capacity of the condenser should be
A nuclear bomb exploded 200 km above the surface of moon. The sound of explosion on the moon
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A cane filled with water is revolved in a vertical circle of radius 4 meter and the water just does not fall down. The time period of revolution will be
A bomb of mass 9Kg explodes into two pieces of masses 3Kg and 6Kg. The velocity of the 3Kg mass is 16 ms-1. Then kinetic energy of 6Kg mass is
The photoelectric threshold wavelength of a certain metal is 3000Å. If the radiation of 2000Å is incident on the metal
A wire extends by 1mm when a force is applied. Double the force is applied to another wire of same material and length but half the radius of cross-section. The elongation of wire in mm will be
Calculate the amount of charge flowing in 2 minutes in a wire of resistance 10Ω when a potential difference of 20 V is applied between its ends
A triode, operating at an anode potential of 300 volts, has an amplification factor of 25. The cut-off grid bias of the triode is approximately:
Two electric charges of 9 μ C and − C are placed 0.16 m apart in air. There will be a point P at which electric potential is zero on the line joining the two charges and in between them. The distance of P from 9 μ C charge is
A 2 kg mass starts from rest on an inclined smooth surface with inclination 30o and length 2 m. How much will it travel before coming to rest on a frictional surface with coefficient of friction of 0.25
An L.C. circuit contains 10 mH inductor and a 25 μ F capacitor. The resistance of the circuit is negligible. The energy stored in the circuit is completely magnetic at time (in milli seconds) being measured from the instant when the circuit is closed
A satellite orbiting the earth in a circular orbit of radius R completes one revolution in 3 h. If orbital radius of geostationary satellite is 36,000 km, orbital radius is
Suppose the sun expands, so that its radius becomes 100 times its present radius and its surface temperature becomes half of its present value. The total energy emitted by it will increase by a factor of
A body of mass 100 g is sliding from an inclined plane of inclination 30o. What is the frictional force experienced if μ = 0.7 ?
If a long hollow copper pipe carries a current, the magnetic field produced will be
The magnitude moment of a magnetic wire of length L is M. What will be its magnetic moment, when it is bent in the form of a semicircle?
In a liquid flowing through a pipe, the pressure difference between its ends is made half and radius is doubled. If the initial rate of flow of liquid was Q, then new rate of flow of liquid through the pipe is
A body falling from a high Minaret travels 40 metres in the last 2 seconds of its fall to ground. Height of Minaret in metres is (take g=10m/s2)
A coin, placed on a rotating turn-table slips, when it is placed at a distance of 9 cm from the centre. If angular velocity of the turn-table is trippled, it will just slip if its distance from the centre 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
The length of a simple pendulum executing simple harmonic motion is increased by 21%. The increase in time-period of the pendulum of increased length is
Two bullets are fired simultaneously, horizontally and with different speeds from the same place. Which bullet will hit the ground first?
A wooden cube first floats inside water when a 200 g mass is placed on it. When the mass is removed the cube is 2 cm above water level. The side of cube is
A beam of white light passing through a prism is split up into its constituent colours. The light which undergoes least deviation is
The moment of inertia of a circular ring about an axis passing through its centre and normal to its plane is 200 gm x cm2. Then its moment of inertia about a diameter is
A capillary tube is immersed vertically in water such that the height of liquid column in it is x. This arrangement is taken into a mine of depth 'd' and the height of liquid column is 'y'. If R is radius of earth, find 'd'in terms of x,y and R.
To deposit one gm equivalent of an element at an electrode, the quantity of electricity needed is
If a scientist says that the efficiency of an engine working at source temperature of 127oC and sink temperature of 27oC is 25%, then
1 videos|1 docs|68 tests
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1 videos|1 docs|68 tests
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