In a parallel circuit with a 30 Ω and 60 Ω resistor connected to a 15 V supply, what is the total current drawn from the source?

In a parallel circuit with a 30 Ω and 60 Ω resistor connected to a 15 V supply, what is the total current drawn from the source?

• A. 0.5 A
• B. 0.75 A
• C. 1.0 A
• D. 1.25 A

Answer: (B)

In a parallel circuit, the same voltage drives each resistor, and the total current drawn from the source equals the supply voltage divided by the equivalent resistance of the parallel network. First find the equivalent resistance of 30 Ω and 60 Ω in parallel: R_eq = (R1×R2)/(R1+R2) = (30×60)/(30+60) = 1800/90 = 20 Ω. Then use Ohm’s law for the whole circuit: I_total = V / R_eq = 15 V / 20 Ω = 0.75 A (three quarters of an ampere). This matches the current value that the correct option represents. The other values would require a different equivalent resistance than the one provided by these two resistors in parallel.

In a parallel circuit, the same voltage drives each resistor, and the total current drawn from the source equals the supply voltage divided by the equivalent resistance of the parallel network. First find the equivalent resistance of 30 Ω and 60 Ω in parallel: R_eq = (R1×R2)/(R1+R2) = (30×60)/(30+60) = 1800/90 = 20 Ω. Then use Ohm’s law for the whole circuit: I_total = V / R_eq = 15 V / 20 Ω = 0.75 A (three quarters of an ampere). This matches the current value that the correct option represents. The other values would require a different equivalent resistance than the one provided by these two resistors in parallel.