651. A force of 10 N makes an angle of 30 degrees with the y-axis. The magnitude of the x-component is:
A. 5 N
B. 8.66 N
C. 10 N
D. Zero
652. A 20-F capacitor is charged to 200 V. Its stored energy is:
A. 4000 J
B. 4 J
C. 0.4 J
D. 2000 J
653. Wheatstone bridge is?
A. Electrical device
B. Instrument
C. Circuit
D. None of the above
654. A hollow metal sphere is charged to potential V. The potential at its center is:
A. V
B. V/2
C. -V
D. 2V
655. A constant current is sent through a helical coil. The coil:
A. Produces zero magnetic field at its center
B. Tends to rotate about its axis
C. Tends to get shorter
D. Tends to get longer
656. An object moving in a circle at constant speed:
A. Must have only one force acting on it
B. Has an acceleration of constant magnitude
C. Is held to its path by centrifugal force
D. None of the above
657. A feather and a lead ball are dropped from rest in a vacuum on the moon. The acceleration of the feather is:
A. Less than that of the lead ball
B. The same as that of the lead ball
C. More than that of the lead ball
D. None of the above
658. Light from some stars shows an apparent change in frequency because of:
A. Relative motion
B. Reflection
C. Diffraction
D. Interference
659. The time rate of displacement is known as:
A. Speed
B. Velocity
C. Acceleration
D. Time Arrow
660. Velocity is a physical quantity that is a:
A. Scalar
B. Vector
C. Time arrow
D. None of these
Admin