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# Current in Series And Parallel Circuits? watch

1. Can someone help me with all of these questions? Explanations would be much appreciated!Attachment 476795476797
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2. (Original post by MrOhms)
Can someone help me with all of these questions? Explanations would be much appreciated!Attachment 476795476797
Fro the first question:

a) Do you know the formula for relating voltage and current with power?

You may need to rearrange the formula to work out the current for one lamp.

b) When you have the current, use Ohms law for the resistance.

c) Once the resistance is known, apply the rules for series and parallel resistances to calculate the total resistance.

For the second part:

Current is the rate at which charge flows. Hence 1 coulomb charge = 1 ampere for 1 second.

The question tells you how long the lamp can light at full brightness. i.e. steady current.

You will need to calculate the current flowing through lamp x and use that together with the total time (in seconds) to calculate the total charge.

Finally energy is work done x time taken. i.e. use the power figure for 1 lamp and time to calculate to the total energy expended.

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Updated: November 9, 2015
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