PHYSICS

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* 1. The energy of the em waves is of the order of 15 keV. To which part of the spectrum does it belong?

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* 2. A rectangular coil of length 0.12 m and width 0.1 m having 50 turns of wire is suspended vertically in a uniform magnetic field of strength 0.2 Weber/m2. The coil carries a current of 2 A. If the plane of the coil is inclined at an angle of 30o with the direction of the field, the torque required to keep the coil in stable equilibrium will be

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* 3. A proton and an alpha particle both enter a region of uniform magnetic field B, moving at right angles to the field B. If the radius of circular orbits for both the particles is equal and the kinetic energy acquired by proton is 1 MeV, the energy acquired by the alpha particle will be

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* 4. A circuit contains an ammeter, a battery of 30 V and a resistance 40.8 ohm all connected in series. If the ammeter has a coil of resistance 480 ohm and a shunt of 20 ohm, the reading in the ammeter will be

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* 5. A series R-C circuit is connected to an alternating voltage source. Consider two situations
(a) When capacitor is air filled.    (b) When capacitor is mica filled.
Current through resistor is i and voltage across capacitor is V then

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* 6. Two metal wires of identical dimensions are connected in series. If  and  are the conductivities of the metal wires respectively, the effective conductivity of the combination is

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* 7. The value of coefficient of volume expansion of glycerin is 5 10–4 K–1. The fractional change in the density of glycerin for a rise of 40o C in its temperature is

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* 8. If potential (in volts) in a region is expressed as V (x, y, z) = 6 xy – y + 2 yz, the electric field (in N/C) at point (1, 1, 0) is

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* 9. A parallel plate air capacitor has capacity ‘C’ distance of separation between plates is ‘d’ and potential difference ‘V’ is applied between the plates. Force of attraction between the plates of the parallel plate air capacitor is

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* 10. In an astronomical telescope in normal adjustment a straight black line of length L is drawn on inside part of objective lens. The eye-piece forms a real image of this line. The length of this image is I. The magnification of the telescope is

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