2.2) A resistor is connected across the terminals of a 9.0-V battery, which delivers 2.2 x 105 J of energy to the resistor in 5.0 hours. What is the resistance of the resistor?
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) A resistor is connected across the terminals of a 9.0-V battery, which delivers 2.2 x 10^5 J of energy to the resistor in 5.0 hours. What is the resistance of the resistor?
Power in watts = Energy in joules ÷ Time in seconds
Time = 5 hour * 60 min/hr * 60 min/s = 18,000 seconds = 1.8 * 10^4 s
Power in watts = 2.2 * 10^5 ÷ 1.8 * 10^4
and
Power = V * I
V = I * R, I = V / R
P = V^2 / R
2.2 * 10^5 ÷ 1.8 * 10^4 = 9^2 / R
Solve for R
Power in watts = Energy in joules ÷ Time in seconds
Time = 5 hour * 60 min/hr * 60 min/s = 18,000 seconds = 1.8 * 10^4 s
Power in watts = 2.2 * 10^5 ÷ 1.8 * 10^4
and
Power = V * I
V = I * R, I = V / R
P = V^2 / R
2.2 * 10^5 ÷ 1.8 * 10^4 = 9^2 / R
Solve for R
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P=V^2/R
Energy/Time=Voltage^2/Resistance
Isolate
Energy/Time=Voltage^2/Resistance
Isolate