3. Electrical fundamentals - Q&A
168 questions found
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Potentiometers are used as a
- variable voltage source.
- variable resistor.
- variable current source.
Potentiometers are used as voltage dividers are the not? they have 3 connections, surely a rheostat would be a better variable resistor?
The 5th coloured band on a resistor represents the
- reliability or temperature coefficient.
- tolerance.
- multiplier.
Isn't it the tolerance in coloured band is represent in the 4th band?
Potentiometers are used as a
- variable voltage source.
- variable resistor.
- variable current source.
Isn't it potentiometer relates to variable voltage source?
What happens to the current in a series resistive resonant circuit?
- It is maximum.
- It is minimum.
- It is zero.
Isn't it that at resonant, we have high impedance hence we should have minimum current flow?
How many amperes will a 28-volt generator be required to supply to a circuit containing five lamps in parallel, three of which have a resistance of 6 ohms each and two of which have a resistance of 5 ohms each?
- 1 ampere.
- 25.23 amperes.
- 1.11 amperes.
resistance, then use ohms law (I=V/R) to find the total current. It is a tricky calculation to do without a calculator, so round the total resistance up (to 1 ohms) then choose the nearest answer for I.
What is the current in the circuit with a resistance of 8 ohms, inductive reactance of 12 ohms, capacitive reactance of 18 ohms with 20 volts applied across it?
- 10 amps.
- 1 amp.
- 2 amps.
Can anyone explain me this one...?
The 5th coloured band on a resistor represents the
- reliability or temperature coefficient.
- tolerance.
- multiplier.
then what is 4th colored band for????
In the circuit shown, the power developed across the 10 kilo ohm resistor is
- 250 mW.
- 250 W.
- 50 mW.
Please Explain 250mW as answer
A transformer has 1200 turns primary and 4800 turns secondary. What value of load resistance would be required to give a reflected impedance of 1000 ohms?
- 4 kOhm.
- 1 kOhm.
- 16 kOhm.
How to do it?
The circuit shown is at resonance. If the value of the inductance is trebled, the impedance will
- stay the same.
- treble.
- reduce by one-third.
parallel circuit dynamic impedance Z=L/CR. so inductance trebled impedance also treble.
is it correct ?
A paramagnetic material has a relative permeability of
- zero.
- less than unity.
- greater than unity.
why?
Reactive sparking is reduced by
- interpoles.
- compensating windings.
- auxiliary windings.
why interpoles?
If the cross-sectional area of a conductor is doubled, with voltage constant, the current will
- remain constant.
- double.
- halve.
anybody can help me explain about this?
A capacitor is fully charged after 25 seconds to a battery voltage of 20 Volts. The battery is replaced with a short circuit. What will be the voltage across the capacitor after one time constant?
- 0 volts.
- 7.36 volts.
- 12.64 volts.
how to do this question ?
after one time constant voltage is 32.8%?//
The SI unit of work is the
- Watt.
- Newton Meter.
- Joule.
is Nm and joule same?
If a 1 ohm circuit produces a 50 W output, the phase angle is
- 45degrees.
- 0degrees.
- 90degrees.
how?? plx explain
What is the PD of a circuit which has a 40 mA current and a 1 kilohm resistance?
- 40 V.
- 400 V.
- 4 V.
What is the PD of a circuit which has a 40 mA current and a 1 kilohm resistancese
An atom contains
- hydrogen.
- molecules.
- electrons.
what would be the right answer