Electrical Engineering - Series Circuits - Discussion
Discussion Forum : Series Circuits - General Questions (Q.No. 5)
5.
Which of the following series combinations dissipates the most power when connected across a 120 V source?
one 220 
resistor
resistortwo 220 resistors
resistorsthree 220 resistors
resistorsfour 220 resistors
resistorsDiscussion:
44 comments Page 1 of 5.
Jeyaraj N said:
1 decade ago
ANS: A
Just think when resistance keep on incresing accros the voltage source, there will not be a current at the maximum resistance, so ther will not be a power dessipation at max resistance (consider open).
Imagine when your reistance is minimum (consider short) accros voltage source, current will be high and your power desipation also will be high.
Just think when resistance keep on incresing accros the voltage source, there will not be a current at the maximum resistance, so ther will not be a power dessipation at max resistance (consider open).
Imagine when your reistance is minimum (consider short) accros voltage source, current will be high and your power desipation also will be high.
Lavanya said:
1 decade ago
Power= v*i =v* (v/r) = v^2 /r.
P= v^2/r it implies that the resistance and power are having inverse relation, so by this we can conclude that as resistance is less power dissipation will be more. From given options one 220 ohm resistor is less compared to other options.
P= v^2/r it implies that the resistance and power are having inverse relation, so by this we can conclude that as resistance is less power dissipation will be more. From given options one 220 ohm resistor is less compared to other options.
Harpreet said:
1 decade ago
V=IR
P=VI
P=V^2/R
WHEN R=220 then power will maximum
now r is denominator so if we increses r then "P" will reduces so p will maximun when r=220
now in option
anser is "A" one resistor in series so right answer
in second option two resistor in series means R increses
P=VI
P=V^2/R
WHEN R=220 then power will maximum
now r is denominator so if we increses r then "P" will reduces so p will maximun when r=220
now in option
anser is "A" one resistor in series so right answer
in second option two resistor in series means R increses
Anand said:
1 decade ago
Nice explanation Lavanya
Shikha said:
1 decade ago
Very good explanation Harpreet.
Balaji said:
1 decade ago
Nice explanation by lavanya.
Hemraj said:
1 decade ago
In this case
P=i^2*r power dissipation is perportional to the ressitace. So more resistace causes of more power dissipation.
P=i^2*r power dissipation is perportional to the ressitace. So more resistace causes of more power dissipation.
Sadik pasha said:
1 decade ago
In series, number of resistors increase total resistance increase so resistance increase current decrease so power dessipation less.
Himanish said:
1 decade ago
YES I am also having the same confusion....
P=VI
V=IR
So P = (I^2)R
BUT again P = (V^2)/R
These statements are contradictory but both are true...
P=VI
V=IR
So P = (I^2)R
BUT again P = (V^2)/R
These statements are contradictory but both are true...
Mohit said:
1 decade ago
If you know that in domestic wiring we have parallel connection to minimize power dissipation.
If we do in series then voltage will be low and power dissipation will be high.
Think about it.
If we do in series then voltage will be low and power dissipation will be high.
Think about it.
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