Brightness of Light Bulbs Ranking Task

[seto6]

Homework Statement

Consider a circuit containing five identical light bulbs and an ideal battery. Assume that the resistance of each light bulb remains constant. Rank the bulbs (A through E) based on their brightness.
Rank from brightest to dimmest. To rank items as equivalent, overlap them.

Homework Equations

V=IR, junction law and loop law

The Attempt at a Solution

i use that fact that more resistance means that less current flow by looking at the pic the current in A&B are the same, but the current in C is greater than in D&E where current in D&E are same b/c of series. there for conclude that C>(A=B)>(D=E)

can any 1 tell me if this is right please!

 

[seto6]

its right

 

[Krize]

If anyone didn't mind me asking, I was wondering WHY Bulb C has less resistance compared to Bulb A or B?

 

[deadkitty]

It doesn't have less resistance, all resistances are the same. It has more voltage because the equivalent resistance of RcRdRe is greater than that of RaRb. If you link brightness to power (P=I*V) and Rab has the same current as Rcde, then because the voltage is higher Rc has more power.

 

[rwisz]

Your reasoning is correct. In a series circuit, the current is the same at all points, so the bulbs with the least resistance (A and B) will be the brightest, followed by C, and then D and E which have the most resistance. This is because more resistance means that more energy is being used up by the resistance, so less energy is available to light up the bulb. Therefore, the ranking from brightest to dimmest would be A=B>C>D=E.