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PART I PHYSICS

2. A particle of charge q and mass m is moving in a circular orbit of radius r with angular speed . Another particle of charge 2 q and mass 2 m is moving in a circular orbit of radius 2 r with the same angular speed . Let 1 and 2, respectively, be themagnitudes of the magnetic dipole moments of the two particles arising because of

their orbital motion. Then the ratio 2 / 1 is equal to

A) 2 B) 4 C) 8 D) 16

3. Three capacitors of capacitances 2 F, 4 F and X F are connected in series. If theresultant capacitance is 12/11 F, what is the value of X ?

A) 6 F B) 8 F C) 5 F D) 4 F

4. The resistance of a thin silver wire is 1.0 at 20 C. The wire is placed in a liquid bathand its resistance rises to 1.2 . What is the temperature of the bath? The temperatureco-efficient of resistance ( ) for silver is 4 10 3/ C.

A) 73 C B) 70 C C) 69 C D) 72 C

5. Two insulating plates are both uniformly charged in such a way that the potentialdifference between them is V 2 V1 = 20 V (i.e. plate 2 is at a higher potential). The

plates are separated by a distance d = 0.1 m and can be treated as infinitely large. Anelectron is released from rest on the inner surface of plate 1. What is its speed when it

hits plate 2 ?

A) 2.65 106 m/s B) 7.02 1012 m/s C) 1.87 106 m/s D) 3 108 m/s

1. Three equal charges + Q each are placed on the vertices of an equilateral triangle. Acharge + q is initially placed at the centre of the triangle. If this charge (+ q) is slightlydisplaced towards a vertex and left free, the charge will

A) continue moving towards the corresponding vertexB) move away from the corresponding vertexC) return back to the centreD) oscillate about the centre

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7/29/2019 Vit Physics

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6. A long straight wire carries a constant current of 5 A. At a distance of 10 cm from thestraight wire, a shorter wire of length 10 cm and mass 3 g is kept parallel to it andcarries a current of 3 A. If the shorter wire is released from its position, itsacceleration just after being released is

A) 103

m/s2

B) 2 103

m/s2

C) 4 103

m/s2

D) 5 103

m/s2

7. Two electron beams having velocities in the ratio of 1:2 are separately subjected toregions of magnetic field strength in the ratio of 1:2, respectively. The ratio of the radiiof the circular paths they will traverse will be

A) 1:4 B) 4:1 C) 1:2 D) 1:1

8. An alternating current, )sin(0 tii passes through an electrical circuit. If is the

angular frequency and T is the time period of the alternating current, the thermal energydeveloped in a resistor R in the circuit during one time period will be

A) I 02RT/2 B) I 02RT/4 C) zero D) I 02RT

9. An ideal transformer with a step up ratio of 100 operates with an input voltage of 230V and current of 5 A. The output current at the secondary will be

A) 0.05 A B) 0.5 A C) 0.005 A D) 500 A

10. The electric field component of an electromagnetic radiation is given by )()10(sin10 18 vtxmiE . The wavelength of the electromagnetic radiation is

A) 2 10 8 m B) 2 10 7 m C) 10 8 m D) ( /2) 10 8 m

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