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If the battery has a voltage of 9 v and the light bulbs have resistance of 10 ohms 20 ohms and 30 ohms What is the voltage across light bulb 2?
Wiki User
∙ 15y ago
Assume you mean resistors in a series ckt, since in a parallel ckt the answer is 9V.
First solve for total current: I=E/Rtotal Rt=10+20+30, or 9/60, so 150ma
then for each R:
E=IR
R1=10, so 10*.15=1.5
R2=20, so 20*.15=3.0
R3=30, so 30*.15=4.5
The source 9V= the sum of the voltage drops as a sanity check.
Wiki User
∙ 15y ago
Wiki User
∙ 15y agoSee my prior answer on this ckt.
Briefly Itotal =9/60=.15=150ma
Vr2=IR=.15*20=3volts
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How are light bulbs efficiency increased?
The brightness of a standard bulb is directly proportional to the amount of voltage drop across the bulb itself. Thus, to increase the brightness :-Pass more current across the bulb by reducing the resistance of the circuitIncrease the voltage across the bulb, or the circuit. Change the supply.
Is it sensible for the TV to be connected in series with the light bulbs?
Connecting light bulb is equivalent to connecting a resistance. If you have connected light bulb, there will be some voltage drop across it and your TV may not get sufficient voltage. However if resistance is not big enough, than it wont have any effect.
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