30 câu hỏi
Which of the following depends on the charging and discharging rate of a capacitor?
Time constant
Current
Power
Voltage
What is the initial current while charging a capacitor?
High
Low
0
Cannot be determined
What is the final current while charging a capacitor?
High
Zero
Infinity
Low
Capacitor is a device used to__________
Store electrical energy
Vary the resistance
Store magnetic energy
Dissipate energy
Capacitor stores which type of energy?
Kinetic energy
Vibrational energy
Potential energy
Heat energy
Capacitor blocks__________ after a long time.
Alternating current
Direct current
Both alternating and direct current
Neither alternating nor direct current
Which of the following is a passive device?
Transistor
Rectifier
Capacitor
Vacuum Tubes
For which medium is capacitance high?
Air
Mica
Water
Metal
Which component in the DC generator produces a magnetic field?
Stator
Commutator
Armature
Carbon brushes
Which component in the alternator produces a magnetic field?
Frame
Stator
Regulator
Rotor
At the start of the engine, the charging voltage is _______
Lower
Higher
Same
Zero
In an alternator, which component controls the output?
Voltage regulator
Cutout relay
Current regulator
Diode
What is the material of an alternator frame?
Cast iron
Brass
Copper
Aluminum
If the lead-acid cell has a total of 17 cells, then what is the number of positive plates?
9
8
7
6
Which of the following is not an advantage of the alternator?
Higher output
Lower weight
Less maintenance
High efficiency
Field coils in a generator produce permanent magnet.
True
False
What is the color of a positive plate of a lead-acid battery?
White
Grey
White
Brown
What gets deposited on the plates of a discharged lead-acid battery?
PbO2
Pb2O4
Pb
PbSO4
What is the number of positive plates in a battery cell?
One more than the negative plates
Two less than the negative plates
One less than the negative plates
Two more than the negative plates
What is a maintenance-free battery?
A battery having lead-antimony plate grid
A battery having lead-calcium plate grid
A battery does not contain acid
A battery does not contain water
Which of the following is the advantage of alkaline battery?
High energy density
Good discharge characteristics over a wide range of temperature
The specific gravity of electrolyte remains the same
Cheap raw materials are used
Which of the following is the best method to measure the speed?
Mechanical tachometer
Electrical tachometer
Magnetic pickup
Mechanical counters
The function of the ignition system is to _____________ the flame propagation process.
Stop
Initiate
Balance
None of the mentioned
The total enthalpy required to cause the flame to be self-sustaining and promote ignition, is given by the product of the surface area of the spherical flame and the enthalpy per unit area.
True
False
A spark can be caused by applying a sufficiently low voltage between two electrodes separated by a gap.
True
False
An ignition process obeys the law of ______________
Conservation of mass
Conservation of energy
Conservation of momentum
None of the mentioned
As air is a poor conductor of electricity, an air gap in an electric circuit acts as a high _____________
Conductor
Resistance
Ignition
None of the mentioned
An ignition system should provide a good spark between the _____________ of the plugs at the correct timing.
Cathodes
Anodes
Electrodes
None of the mentioned
An ignition system should be heavy, effective and reliable in service.
True
False
The interference from the low voltage source should not affect the functioning of the radio and television receivers inside an automobile.
True
False