If my memory serves me right, the power counts P=I^2*R, so first you have to calculate the current flowing in the circuit using the formula I=U/R, we have 4.5V/(10+5+0.5) or 0.65A, then P=0.65*0.65*10= 4.225W
Knowing the current in the circuit = 0.29A Calculate the voltage drop across the resistor according to the formula: U=I x R 0.29x10 ohms=2.90V Calculate the power dissipated on the resistor according to the formula: P=U squared /R 2.90*2.90/10 = 0.84W
