Solving a Circuit: What Will the Voltmeter Show?

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The discussion revolves around a circuit where the emf source resistance equals the bulb's resistance, and the voltmeter reads 6 volts. When the bulb burns out, the question arises about what the voltmeter will display. The equation EMF=IR+Ir is referenced, with the understanding that r equals R and IR is 6V. A participant concludes that the EMF would be 12V based on the relationship established in the equation. The thread seeks clarification on the voltmeter's reading after the bulb's failure.
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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.
 
Last edited:
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EMF=IR+Ir
In the above equation it is given that r = R and IR = 6 V.
Then what is the EMF?
 
Last edited:
EMF=2IR=12V Thanks !
 

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