Please post a method.
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Last edited by Jas1947; 16-10-2016 at 23:14.
- 16-10-2016 23:13
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- 17-10-2016 09:47
we know the PD across RA and RB is the same because they are in parallel with each other.
and the resistance of RB is 2x the resistance of RA so the current in RB must be some proportion of the current in RA because I=V/R
and we know power is given by P=IV
so we know the power dissipation of RB as a proportion of the power dissipated in RA
Now the current in RC will be equal to the sum of the currents in RA and RB
so we can find the power dissipation in RC using the rule P=I2R
then we just need to add the 3 power dissipations together to get the total being supplied by the battery.