In a transformer 220 A.C. voltage is increased to 2200 volts. If the number of turns in the secondary are 2000, then the number of turns in the primary will be
In a photo electric experiment the maximum velocity of photo electons emitted
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Two wires of same metal have the same length but their cross sections are in the ratio 3:1. They are joined in series. The resistance of the thicker wire is 10 Ω. The total resistance of the combination is
If elements with principal quantum number n >= 4 were not allowed in nature, then, the number of possible elements would be
If a cell of constant electromotive force produces the same amount of heat during the same time in two independent resistances R₁ and R₂, when connected separately one after the other, across the cell, then the internal resistance of the cell is
A wire of radius r has resistance R. If it is stretched to a radius of 3r/4, its resistance becomes
The energy required to charge a parallel plate condenser of plate separation d and plate area of cross-section A such that the uniform electric field between the plates is E, is
Determine the current drawn from a 12 v supply with internal resistance 0.5Ω by the infinite network shown in the figure . Each resistor has Ω resistance
A cell whose e.m.f. is 2V and internal resistance is 0.1Ω, is connected with a resistance of 3.9Ω. The voltage across the cell terminal will be
In an electron gun, the electrons are accelerated by the potential V. If e is the charge and m is the mass of an electron, then the maximum velocity of these electrons will be
A bar magnet dropped into a coil of a conducting wire, along its axis, will fall with an acceleration
A generator at a utility company produces 100 A of current at 4000 V. The voltage is stepped up to 240000 V by a transformer before it is sent on a high voltage transmission line. The current in transmission line is
A 220 V, 1000 watt bulb is connected across a 110 V mains supply. The power consumed will be
Consider the situation in the figure. The work done in taking a point charge from P to Ais WA, from P to B is WB and from P to C is WC.
A dust particle of mass 10-3 gm is stationary between the plates of a horizontal parallel plate capacitor of 0 .016m separation which is connected to a voltage of 100V. How many fundamental charges (e = 1.6 x 10-19 C) the dust particle carries
A capacitor of capacity C1 is charged upto V volt and then connected to an unchanged capacitor of capacity C2. The potential difference across each capacitor will be
A charge q is placed at the corner of a cube of side l. The electric flux passing through the cube is
Dielectric constant of a medium is unity. Its permittivity will be:
If in a photoelectric experiment, the wavelength of incident radiation is reduced from 6000Å to 4000Å, then
When a centimeter thick surface is illuminated with light of wavelength λ, stopping potential is V. When the same surface is illuminated by light of wavelength 2 λ, stopping potential is V/3. Threshold wavelength for metallic surface is
In Ramsden's eye-piece, the distance from the eye lens at which the image due to objective of focal length f is formed is
Which of the following spectrum have all the frequencies from high to low frequency range ?
While a collector emitter voltage is constant in a transistor, the collector current changes by 8.2 m A .When the emitter current changes by 8.3 m A, the value of forward current ratio hfe is
When the p-end of the p-n junction is connected to the negative terminal of the battery and the n-end to the positive terminal of the battery, then the p-n junction behaves like