# The Christmas Lights.

The Christmas tree is decorated with a garland of light bulbs are connected in series. One bulb burns out and the new electric circuit is made without the burned light bulb. Is the light getting brighter or dimmer?

###### Solution. Posted on Wednesday, November 19, 2014.

According the Ohm’s law: I= V/R and the total resistance in a series DC circuit can be find by the formula R=R1+R2+R3+…+Rn.
So, if we have less bulbs, it is meant that the overall resistance is smaller. The voltage is not change and finally, electric current will be stronger.
In conclusion, the light is getting brighter.

## 8 thoughts on “The Christmas Lights.”

1. gabby says:

Each light bulb has some resistance, and the overall resistance is the sum of resistances of all bulbs. One less bulb means the overall resistance is smaller. Since the voltage is not changed, the current is increased and the bulbs are brighter.

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• Johnny B says:

But you said the bulbs were connected in series not parallel?

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• Johnny B says:

If the bulb burns out the circuit is broken and all the lights go out.

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• Yes …and the new electric circuit is made without the burned light bulb.

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2. Johnny B says:

Of course ! This is one of my problems with problems, I frequently misread them, no matter how many times I read them. Thanks.

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