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
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
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
Waves emitted from the antenna are__________________?
(A) Sound waves
(B) Electromagnetic waves
(C) Radio waves
(D) Modulated waves
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
Electromagnetic waves travel in free space with the speed of___________________?
(A) λ-rays
(B) Positive rays
(C) Cathode rays
(D) More than sound waves
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
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
If a glass plate is inserted in between the plate of a capacitor in series with a lighted bulb the brightness of the bulb________________?
(A) Remains same
(B) Brightness increases
(C) Brightness decreases
(D) No light
A 100µF capacitor with a 12V source in series having frequency 50Hz will offer a capacitive reactance of about______________?
(A) 32Ω
(B) 62Ω
(C) 50Ω
(D) 100Ω