Source current with parallel branches: Three 47 Ω resistors are connected in parallel across a 110 V source. Approximately how much current is drawn from the source?

Introduction / Context:
When multiple equal resistors are placed in parallel across a fixed-voltage source, the total resistance decreases and the source current increases. This question checks quick estimation skills for parallel equivalents and Ohm’s law at the source level.

Given Data / Assumptions:

• Three identical resistors, each R = 47 Ω.
• All in parallel across V = 110 V.
• Assume ideal conditions (no wire resistance or source droop).

Concept / Approach:

Equivalent of N equal resistors in parallel is R_eq = R / N. The source current is I_source = V / R_eq. Alternatively, compute branch current and multiply by the number of branches.

Step-by-Step Solution:

Verification / Alternative check:

Both methods agree within rounding. The closest option is 7.06 A, which matches reasonable rounding of the calculation.

Why Other Options Are Wrong:

2.3 A is roughly one branch current, not the total. 780 mA and 47 mA are far too low. 0.706 A is off by a factor of 10.

Common Pitfalls:

Forgetting to divide R by the number of equal branches, or forgetting to sum the branch currents when using the branch method.

Final Answer:

7.06 A