Simple Circuit diagram Question

[skykiller95]

The diagram shows identical lamps X and Y connected in series with a battery. The lamps light with normal brightness. A third lamp Z is connected in parallel with lamp X.

What happens to the brightness of lamp Y?
A) Brighter than normal
B) Normal
C) Dimmer than normal
D) Very dim (cannot be seen)


I'm completely clueless about it and slightly confused. Any help would be appreciated.

 

[daveb]

Think of it in terms of resistors - is there a difference in total resistance between the first situation and the second?

 

[Doc Al]

What do you think happens? Hint: See if you can figure out how the current passing through lamp Y changes (if it does).

 

[skykiller95]

Hmms, I would have to say, yes?

 

[skykiller95]

What do you think happens? Hint: See if you can figure out how the current passing through lamp Y changes (if it does).

Hmm, wouldn't the additional lamp added in parallel alter the current in the entire circuit?

 

[Doc Al]

Hmm, wouldn't the additional lamp added in parallel alter the current in the entire circuit?

Yes, so what happens to the current going through lamp Y? Increase, decrease, or remain the same?

 

[skykiller95]

Yes, so what happens to the current going through lamp Y? Increase, decrease, or remain the same?

I'm not so sure, but I would say increase.

 

[Doc Al]

I'm not so sure, but I would say increase.

Guessing doesn't count.

Take daveb's hint: The lamps are like resistors. What happens to the total resistance and thus to the current?

 

[skykiller95]

Guessing doesn't count.

Take daveb's hint: The lamps are like resistors. What happens to the total resistance and thus to the current?

Total resistance decreases, current increases.

 

[Doc Al]

Total resistance decreases, current increases.

Good!

 

[skykiller95]

Good!

Oh so the bulb is brighter?
Thanks for helping guys!

 

[Doc Al]

Oh so the bulb is brighter?

Right.

Adding that resistor in parallel with X drops the total resistance, which increases the current flowing through Y. More current means a brighter bulb.