Percent Change Of current when the switch is closed

[ChrisWM]

Homework Statement

By what percent does the current through A change when the switch is closed?

I found the value of the current to be .174 A when the switch is closed and value of the current when the switch is open to be .181 A.

Relevant Equations

final-initial/initial

(.174A-.181A)/.181A=-3.86% but it says it wrong, and I did (.181A-.174A)/.174A =4.02% but this was wrong too. I've tried 3.87%,3.86%,-3.87%,-3.67%,4.02%, and -4.02% but all were wrong. I'm really not sure what to do here.

 

[cnh1995]

Is there a circuit diagram?

 

[ChrisWM]

Here you go!

 

[ChrisWM]

Here is the actual problem; For an ideal battery (r = 0 Ω), closing the switch in (Figure 1)does not affect the brightness of bulb A. In practice, bulb A dims just a little when the switch closes. To see why, assume that the 1.50 V battery has an internal resistance r = 0.30 Ω and that the resistance of a glowing bulb is R = 8.00 Ω.

 

[ChrisWM]

Is there a circuit diagram?