A solid metallic sphere has a charge +3Q. Concentric with this sphere is a conducting spherical shell having charge -Q. The radius of the sphere is a and that of the spherical shell is b(b > a). What is the electric field at a distance R(a < R < b) from the centre
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(a) |
(b) |
(c) |
(d) |
(c) 
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Assertion : Two electric bulbs of 50 and 100 W are given. When connected in series 50 W bulb glows more but when connected parallel 100 W bulb glows more.
Reason : In series combination, power is directly proportional to the resistance of circuit. But in parallel combination, power is inversely proportional to the resistance of the circuit.
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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. |
In an adjoining figure are shown three capacitors 
and 
joined to a battery. The correct condition will be (Symbols have their usual meanings)
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(a) |
(b) |
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(c) |
(d) |
When objects at different distances are seen by the eye, which of the following remains constant
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(a) The focal length of the eye lens |
(b) The object distance from the eye lens |
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(c) The radii of curvature of the eye lens |
(d) The image distance from the eye lens |
For a given triode μ = 20. The load resistance is 1.5 times the anode resistance. The maximum gain will be
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(a) 16 |
(b) 12 |
(c) 10 |
(d) None of the above |
The slope of frequency of incident light and stopping potential graph for a given surface will be
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(a) h |
(b) h/e |
(c) eh |
(d) e |
The thermo e.m.f. of a thermocouple varies with the temperature θ of the hot junction as 
in volts where the ratio a/b is 700℃. If the cold junction is kept at 0℃, then the neutral temperature is
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(a) 700℃ |
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(b) 350℃ |
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(c) 1400℃ |
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(d) No neutral temperature is possible for this thermocouple |
Ratio between total intensity of magnetic field at equator to poles is
| (a) 1 : 1 | (b) 1 : 2 | (c) 2 : 1 | (d) 1 : 4 |
Which of the following gives the value of magnetic field according to, Biot-Savart’s law’
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(a) |
(b) |
(c) |
(d) |
In a charged capacitor, the energy resides
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(a) The positive charges |
(b) Both the positive and negative charges |
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(c) The field between the plates |
(d) Around the edge of the capacitor plates |
