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A LC circuit is in the state of resonance. If C = 0.1μF and L = 0.25 henry. Neglecting ohmic resistance of circuit what is the frequency of oscillations
From the formula, the frequency of oscillation is
f=1/2π(LC)^{1/2}
=1/2π(0.25×0.1×10^{−6})^{1/2}
=1007Hz
The photoelectic work function for a metal surface is 4.125eV. The cutoff wave length for this surface is
Work function W_{0} = hc/λ
An air capacitor of capacity C = 10μ F is connected to a constant voltage battery of 12 volt. Now the space between the plates is filled with a liquid of dielectric constant 5. The charge that flows now from battery to the capacitor is
C = 10 μ F
Charge in capacitor q = CV
= 10 x 12
= 120 μ C
On keeping liquid of dielectric constant5, capacity will becomes of 5 time.
∴ Charge q = 5 x 120
= 600 μ C
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
Consider telecommunication through optical fibres. Which of the following statements is not correct
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Three unequal resistors in parallel are equivalent to resistance 1 Ω . If two of them are in the ratio 1 : 2 and if no resistance value is fractional, the largest of the three resistances in ohms is
The temperature coefficient of a resistance wire is 0.00125 per degree. The resistance at 300 K is 1 ohm. At what temperature its resistance will be 2 ohm, at
An electron and a proton have same deBroglie's wavelength. The kinetic energy of an electron is
Lenz's law is a consequence of the law of conservation of
If 2.2 kW power is transmitted through a 10 Ω line at 22000 V, the power loss in the form of heat will be
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A charge q is placed at the corner of a cube of side l. The electric flux passing through the cube is
Eight cubes, each side l, are required to form a Gaussian surface
So that the charge q at the corner of a small cube appears at the centre of the bigger cube
According to Gauss's law, the electric flux through the bigger cubes = q/∈_{0}
Hence the electric flux through the given small cube = q/8∈_{0}
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A chain reaction is fission of uranium is possible because
Two nuclei have their mass numbers in the ratio of 1:3 . The ratio of their nuclear densities would be
The nuclear density does not depend on mass numbers
So it can, safely, be concluded that for all nuclei possess nearly the same density
A radio active sample has a half life of 5 days. To decay from 8 micro curies to 1 microcurie, the number of days taken will be
A ray of light passes through an equilateral prism such that the angle of incidence is equal to the angle of emergence and the latter is equal to 3/4 the angle of prism. The angle of deviation is
The electric circuit used to get smooth d.c. output from a rectifier circuit is called
A pn photodiode is fabricated from a semiconductor with a band gap of 2.5 eV. It can detect a signal of wavelength:
If no external voltage is applied across PN junction, there would be
When a PN junction diode is reverse biased, the flow of current across the junction is mainly due to
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When light wave suffer reflection at the interface between air and glass, the change of phase of reflected wave is equal to
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