If λ0 is the de-Broglie wavelength for a proton accelerated through a potetial difference of 100 V, the de-Broglie wavelength for α -particle accelerated through the same potential difference is
The number of dry cells, each of e.m.f. 1.5 volt and internal resistance 0.5 ohm that must be joined in series with a resistance of 20 ohm so as to send a current of 0.6 ampere through the circuit is
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The resistance of a coil is 4.2 Ω at 100ºC and the temperature coefficient of resistance of its material is 0.004/ºC. Its resistance at 0ºC is
A body of mass 0.05kg is observed to fall with an acceleration of 9.5ms-2. The opposing force of air on the body is........(g = 9.8ms-2)
The electric field inside a charged conductor of radius r is
Power delivered by the source in the circuit is maximum, when
Acceleration due to gravity is 'g' on the surface of the earth. The value of acceleration due to gravity at a height of 32 km above earth's surface is
Two identical conducting plates of plate area A are separated by a distance d to form a parallel plate air capacitor. Now a metal sheet of thickness d/2 is inserted between the plates of the capacitor. The ratio of capacitance before the insertion of plate and after the insertion of plate is
A galvanometer has a resistance of 25 Ω and a maximum of 0.01 A current can be passed through it. In order to change it into an ammeter of range 10 A, the shunt resistance required is
To convert a galvanometer into a voltmeter, we must connect a
At the neutral point, horizontal component of the magnetic field due to a magnet is
A car moves for half of its time at 80 km/h and for rest half of time at 40 km/h. Total distance covered is 60 km. What is the average speed of the car?
A stone is just released from the window of a train moving along a horizontal straight track. The stone will hit the ground following
A cricketer can throw a ball to a maximum horizontal distance of 100 m. The speed with which he throws the ball is (to the nearest integer)
Among electron, proton, neutron and α - particle the maximum penetration capacity is for
A mass m is vertically suspended from a spring of negligible mass. The system oscillates with a frequency n. What will be the frequency of the system, if a mass 4m is suspended from the same spring ?
A spring has a certain mass suspended from it and its period for vertical oscillation is T. The spring is now cut into two halves and the same mass is suspended from one of the halves. The period of verticle oscillation is now
A circular disc is to be made by using iron aluminium, so that it acquires maximum moment of inertia about its geometrical axis. It can be obtained with
A ray of light is incident on a surface of glass slab at an angle 450 . If the lateral shift produced per unit thickness is the angle of refraction produced is
Platinum and silicon are heated upto 250ºC and after then cooled. In the process of cooling
70 calories of heat are required to raise the temperature of 2 moles of an ideal gas at constant pressure from 30ºC to 35ºC. The amount of heat required to raise the temperature of the same sample of the gas through the same range at constant volume is nearly (Gas constant = 1.99 cal/K-mole)
Which of the following pair of physical quantities had same dimensional formula?
Who was the first to demonstrate the phenomenon of interference of light?
The circuit shown in the figure contains two diodes each with a forward resistance of 50 ohms and with infinite backward resistance .If the battery voltage is 6V, the current through the 100 ohm resistance (in amperes) is
3 videos|10 docs|54 tests
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3 videos|10 docs|54 tests
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