Options:
- A. weaken it
- B. strengthen it
- C. reverse its polarity
- D. demagnetize it completely
View Answer
A. weaken it
Physics
A moving coil galvanometer of resistance 100? gives half scale deflection for a current of 20mA. What will be the potential difference across it ?
Options:
- A. 4 volt
- B. 5 volt
- C. 2 volt
- D. 0.4 volt
View Answer
C. 2 volt
An alternating current or voltage_____________________?
Options:
- 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
View Answer
C. changes its direction again and again
Electromagnetic waves travel in free space with the speed of___________________?
Options:
- A. ?-rays
- B. Positive rays
- C. Cathode rays
- D. More than sound waves
View Answer
A. ?-rays
An electromagnetic wave consists of _____________________?
Options:
- 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
View Answer
D. Electric and magnetic fields moving perpendicular to each other
Waves emitted from the antenna are__________________?
Options:
- A. Sound waves
- B. Electromagnetic waves
- C. Radio waves
- D. Modulated waves
View Answer
B. Electromagnetic waves
If capacitance of L-C circuit is made four times then frequency of the circuit becomes___________________?
Options:
- A. Twice
- B. One half
- C. Four times
- D. None
View Answer
B. One half
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__________________?
Options:
- A. Average current
- B. Sinusoidal current
- C. r.m.s current
- D. Net current
View Answer
C. r.m.s current
The deflection for 50 division of galvanometer is decreased to 25 divisions by shunt resistance of 12?. Galvanometer resistance is_____________?
Options:
- A. 18?
- B. 30?
- C. 24?
- D. 12?
View Answer
D. 12?
An alternating current of the r.m.s value of 4.0 A and frequency 50Hz flows in a circuit containing a 10? resistor. The peak current is then ?
Options:
- A. 20A
- B. 20.66A
- C. 6.66A
- D. 5.66A
View Answer
D. 5.66A