Solving a Circuit: What Will the Voltmeter Show?

[goneftw]

Homework Statement

http://imageshack.us/m/508/9977/unlednia.png

The emf source resistance is equal to the bulb's resistance. The voltmeter has some big resistance and it shows 6volts.

What will the voltmeter show when the bulb burns out ?

Homework Equations

I think this is the equation needed : EMF=IR+Ir

The Attempt at a Solution

I don't know how to solve this please give a hint.

 

[rl.bhat]

EMF=IR+Ir
In the above equation it is given that r = R and IR = 6 V.
Then what is the EMF?

 

[goneftw]

EMF=2IR=12V Thanks !