# Amount of power consumed by a non linear light bulb

1. Jul 23, 2012

### oportunity

1. The problem statement, all variables and given/known data

figure 1 shows the relation ship between voltage and current when voltage is applied o a certan light bulb. Next as shown in figure 2, the bulb os connected n series with a 12V battery and 5Ω resitor.
Figure 1
http://imageshack.us/photo/my-images/585/imagnecir.png/
http://imageshack.us/photo/my-images/585/imagnecir.png
Fgure 2
http://imageshack.us/photo/my-images/401/imagnecir2.png/
http://imageshack.us/photo/my-images/401/imagnecir2.png

what is the amount of power consumend by the light bulb?

thanks

2. Jul 23, 2012

### truesearch

The one thing you know is that the (voltage across the bulb) + (voltage across the 5ohm resistor) =12V
The voltage across the resistor is always going to be Ix5.... look up the current axis for the bulb and find waht current will give a (voltage across the bulb) + Ix5 =12 (it works out quite nicely)

3. Jul 23, 2012

### oportunity

ok. thanks

4. Jul 23, 2012

### truesearch

did you get 2A x 2V = 4W for the bulb and 2A x 10V = 20W for the resistor?

5. Jul 23, 2012

### oportunity

yes. thanks

6. Jul 23, 2012