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# AIEEE 2007 Physics

1)  The displacement of an object attached to a spring and executing simple harmonic motion is given by x = 2 X 10-2 cos πt metres. The time at which the maximum speed first occurs is t

1 )   0.5 s

2 )   0.75 s

3 )   0.125 s

4 )   0.25 s

2) In an a.c. circuit the voltage applied is E = E0 sin ωt. The resulting current in the circuit is I = I0 sin (ωt - π/2) . The power consumption in the circuit is given by

1 )  p = E0I0/√2

2 )  P = zero

3 )  p = E0I0/2

4 )  P = √2 E0I0

3) An electric charge 10-3 μ C is placed at the origin (0, 0) of X - Y co-ordinate system. Two points A and B are situated at ( √2, √2) and (2, 0) respectively. The potential difference between the points A and B will be

1 )   9 volt

2 )   zero

3 )   2 volt

4 )   4.5 volt

4) A battery is used to charge a parallel plate capacitor till the potential difference between the plates becomes equal to the electromotive force of the battery. The ratio of the energy stored in the capacitor and the work done by the battery will be

1 )   1

2 )   2

3 )   1/4

4 )   1/2

5) An ideal coil of 10 H is connected in series with a resistance of 5 Ω and a battery of 5V. 2 seconds after the connection is made, the current flowing in amperes in the circuit is

1 )   (1 - e)

2 )   e

3 )    e-1

4 )    (1 - e-1)

6) A long straight wire of radius a carries a steady current i. The current is uniformly distributed across its cross section. The ratio of the magnetic field at a/2 and 2a is

1 )   ¼

2 )   4

3 )   1

4 )   1/2