E denotes electric field in a uniform conductor, I corresponding current through it, 
drift velocity of electrons and P denotes thermal power produced in the conductor, then which of the following graph is incorrect
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(a)
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(b)
|
(c)
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(d)
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(c)
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In Fresnel diffraction, if the distance between the disc and the screen is decreased, the intensity of central bright spot will
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(a) Increase |
(b) Decrease |
(c) Remain constant |
(d) None of these |
The expression for the capacity of the capacitor formed by compound dielectric placed between the plates of a parallel plate capacitor as shown in figure, will be (area of plate = A)
|
(a) |
(b) |
(c) |
(d) |
In human eye the focussing is done by
|
(a) To and fro movement of eye lens |
|
(b) To and fro movement of the retina |
|
(c) Change in the convexity of the lens surface |
|
(d) Change in the refractive index of the eye fluids |
Two point charges (+Q) and (-2Q) are fixed on the X-axis at positions a and 2a from origin respectively. At what positions on the axis, the resultant electric field is zero
|
(a) Only x = |
(b) Only x = - |
(c) Both x = ± |
(d) x = |
Two plates are at potentials –10 V and +30 V. If the separation between the plates be 2 cm. The electric field between them is
|
(a) 2000 V/m |
(b) 1000 V/m |
(c) 500 V/m |
(d) 3000 V/m |
Constantan wire is used in making standard resistances because its
|
(a) Specific resistance is low |
|
(b) Density is high |
|
(c) Temperature coefficient of resistance is negligible |
|
(d) Melting point is high |
A beam of light AO is incident on a glass slab (μ = 1.54) in a direction as shown in figure. The reflected ray OB is passed through a Nicol prism on viewing through a Nicole prism, we find on rotating the prism that
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(a) The intensity is reduced down to zero and remains zero |
|
(b) The intensity reduces down some what and rises again |
|
(c) There is no change in intensity |
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(d) The intensity gradually reduces to zero and then again increases |
The universal property of all substances is
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(a) Diamagnetism |
(b) Ferromagnetism |
(c) Paramagnetism |
(d) All of these |
A constant voltage is applied between the two ends of a metallic wire. If both the length and the radius of the wire are doubled, the rate of heat developed in the wire
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(a) Will be doubled |
(b) Will be halved |
|
(c) Will remain the same |
(d) Will be quadrupled |
