i = V/R
for 20-Ω
i = 9/20
for 30-Ω
i = 9/30
so
total current from battery = 9/20 + 9/30 = 27/60 + 18/60 = 45/60 = 3/4 amp
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or use parallel resistor formula
1/R = 1/R1 + 1/R2
R = R1 R2 /(R1+R2) = 600 / 50 = 12 Ohms
i = V/R = 8/12 = 3/4 amp again
A 20-Ω resistor and a 30-Ω resistor are wired in parallel and connected to a 9.0-V battery.
a. How much current is drawn from the battery?
b. How much power is dissipated in the circuit?
2 answers
Power = volts * amps = 9 * 3/4 = 27/4 watts
1 answer