691. A moving coil galvanometer of resistance 100? gives half scale deflection for a current of 20mA. What will be the potential difference across it ?
A. 4 volt
B. 5 volt
C. 2 volt
D. 0.4 volt

692. An alternating current or voltage_____________________?
A. fluctuates off and on
B. varies in magnitude alone
C. changes its direction again and again
D. changes its magnitude harmonically and reverses its direction of flow after regularly recurring intervals

693. Electromagnetic waves travel in free space with the speed of___________________?
A. λ-rays
B. Positive rays
C. Cathode rays
D. More than sound waves

694. An electromagnetic wave consists of _____________________?
A. Electric and magnetic fields moving parallel to each other
B. Magnetic field moving with velocity of light in space
C. Electric field moving with velocity of light
D. Electric and magnetic fields moving perpendicular to each other

695. Waves emitted from the antenna are__________________?
A. Sound waves
B. Electromagnetic waves
C. Radio waves
D. Modulated waves

696. If capacitance of L-C circuit is made four times then frequency of the circuit becomes___________________?
A. Twice
B. One half
C. Four times
D. None

697. The value of the steady current which when flowing through the same resistor produces heat at the same rate as the mean rate of heat produced by the alternating current is__________________?
A. Average current
B. Sinusoidal current
C. r.m.s current
D. Net current

698. An alternating current of the r.m.s value of 4.0 A and frequency 50Hz flows in a circuit containing a 10Ω resistor. The peak current is then ?
A. 20A
B. 20.66A
C. 6.66A
D. 5.66A

699. A changing magnetic flux produces around itself an induced_______________?
A. Magnetic field
B. Electric field
C. Electromagnetic force
D. Artificial gravitational field

700. The direction of propagation of an electromagnetic waves is________________?
A. Perpendicular to electric field
B. Perpendicular to both electric and magnetic field
C. Perpendicular to magnetic field
D. Parallel to electric and magnetic field