Which of the following quantities increase when wavelength is increased? Consider only the magnitudes.
Explanation:
The focal length of a lens is inversely proportional to the refractive index of the lens and the refractive index of the lens is inversely proportional to the square of wavelength. Therefore, the focal length is directly dependent on wavelength; it increases when the wavelength is increased.
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Assertion : Neutral temperature of a thermocouple does not depend upon temperature of cold junction.
Reason : Its value is constant for the given metals of the couple.
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(a) If both assertion and reason are true and the reason is the correct explanation of the assertion. |
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(b) If both assertion and reason are true but reason is not the correct explanation of the assertion. |
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(c) If assertion is true but reason is false. |
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(d) If the assertion and reason both are false. |
The resistance of a discharge tube is
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(a) Ohmic |
(b) Non-ohmic |
(c) Both (a) and (b) |
(d) Zero |
To get three images of a single object, one should have two plane mirrors at an angle of
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(a) 30° |
(b) 60° |
(c) 90° |
(d) 150° |
Which of the following has the mass closest in value to that of the positron (1 a.m.u = 931 Mev)
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(a) Proton |
(b) Electron |
(c) Photon |
(d) Neutrino |
A circular coil of diameter 7cm has 24 turns of wire carrying current of 0.75A. The magnetic moment of the coil is
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(a) 6.9 |
(b) 2.3 |
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(c) |
(d) |
The electron in a hydrogen atom makes a transition from an excited state to the ground state. Which of the following statements is true
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(a) Its kinetic energy increases and its potential and total energies decrease |
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(b) Its kinetic energy decreases, potential energy increases and its total energy remains the same |
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(c) Its kinetic and total energies decrease and its potential energy increases |
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(d) Its kinetic, potential and total energies decreases |
