A spring of force constant k is cut into lengths of ratio 1: 2 : 3. They are connected in series and the new force constant is k'. Then they are connected in parallel and force constant is k''. Then k' : k'' is
The ratio of resolving powers of an optical microscope for two wave lengths λ1 = 4000 Å and λ2 = 6000 Å is :-
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The two nearest harmonics of a tube closed at one end and open at other end are 220 Hz and 260 Hz. What is the fundamental frequency of the system?
Consider a drop of rain water having mass 1 g falling from a height of 1 km. It hits the ground with a speed of 50 m/s. Take 'g' constant with a value 10 m/s2. The work done by the
(i) gravitational force and the
(ii) resistive force of air is :-
A physical quantity of the dimensions of length that can be formed out of is velocityof light, G is universal constant of gravitation and e is charge] :-
Two rods A and B of different materials are welded together as shown in figure. Their thermal conductivities are K1 and K2. The thermal conductivity of the composite rod will be :-
A capacitor is charged by a battery. The battery isremoved and another identical uncharged capacitoris connected in parallel. The total electrostaticenergy of resulting system :-
In a common emitter transistor amplifier the audio signal voltage across the collector is 3V. The resistance of collector is 3 kΩ. If current gain is 100 and the base resistance is 2 kΩ, the voltage and power gain of the amplifier is :-
Thermodynamic processes are indicated in the following diagram :
Suppose the charge of a proton and an electrondiffer slightly. One of them is – e, the other is(e + De). If the net of electrostatic force and gravitational force between two hydrogen atoms placed at a distance d (much greater than atomicsize) apart is zero, then De is of the order of[Given mass of hydrogen mh = 1.67 × 10–27 kg]
The resistance of a wire is 'R' ohm. If it is meltedand stretched to 'n' times its original length, its newresistance will be :-
The de-Broglie wavelength of a neutron in thermalequilibrium with heavy water at a temperature T(Kelvin) and mass m, is :-
Which one of the following represents forward bias diode ?
A long solenoid of diameter 0.1 m has 2 × 104 turnsper meter. At the centre of the solenoid, a coil of 100 turns and radius 0.01 m is placed with its axiscoinciding with the solenoid axis. The current in thesolenoid reduces at a constant rate to 0A from 4 A in 0.05 s. If the resistance of the coil is 10π2Ω.the total charge flowing through the coil during thistime is :-
Preeti reached the metro station and found that the escalator was not working. She walked up the stationary escalator in time t1. On other days, if she remains stationary on the moving escalator, then the escalator takes her up in time t2. The time taken by her to walk up on the moving escalator will be
Young's double slit experment is first performed inair and then in a medium other than air. It is foundthat 8th bright fringe in the medium lies where 5th dark fringe lies in air. The refractive index of themedium is nearly :-
A beam of light from a source L is incident normallyon a plane mirror fixed at a certain distance x fromthe source. The beam is reflected back as a spoton a scale placed just above the source I. When themirror is rotated through a small angle q, the spotof the light is found to move through a distance yon the scale. The angle q is given by :-
If θ1 and θ2 be the apparent angles of dip observedin two vertical planes at right angles to each other,then the true angle of dip θ is given by :-
Two cars moving in opposite directions approach each other with speed of 22 m/s and 16.5 m/s respectively. The driver of the first car blows a horn having a a frequency 400 Hz. The frequency heard by the driver of the second car is [velocity of sound 340 m/s] :-
Two blocks A and B of masses 3 m and mrespectively are connected by a massless andinextensible string. The whole system is suspendedby a massless spring as shown in figure. Themagnitudes of acceleration of A and B immediatelyafter the string is cut, are respectively :-
A thin prism having refracting angle 10° is made of glass of refractive index 1.42. This prism is combined with another thin prism of glass ofrefractive index 1.7. This combination produces dispersion without deviation. The refracting angleof second prism should be :-
The acceleration due to gravity at a height 1 km above the earth is the same as at a depth d below the surface of earth. Then:-
A potentiometer is an accurate and versatile device to make electrical measurements of E.M.F. because the method involves :-
A spherical black body with a radius of 12 cm radiates 450 watt power at 500 K. If the radius were halved and the temperature doubled, the power radiated in watt would be :-
Figure shows a circuit that contains three identicalresistors with resistance R = 9.0 Ω each, two identical inductors with inductance L = 2.0 m Heach, and an ideal battery with emf ε = 18 V. Thecurrent 'i' through the battery just after the switch closed is,...... :-
Radioactive material 'A' has decay constant '8 λ' andmaterial 'B' has decay constant 'λ'. Initially they havesame number of nuclei. After what time, the ratioof number of nuclei of material 'B' to that 'A' will be 1/e?
The diagrams below show regions of equipotentials:-
A positive charge is moved from A to B in each diagram.
Two astronauts are floating in gravitational free space after having lost contact with their spaceship.The two will :-
The x and y coordinates of the particle at any timeare x = 5t 2t2 and y = 10t respectively, wherex and y are in meters and t in seconds. Theacceleration of the particle at t = 2s is :-
1 videos|26 docs|121 tests
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1 videos|26 docs|121 tests
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