Circuit Fundamentals — question 1 of 10
Write a real answer. It is graded against the question's rubric, and the mastery movement is computed by the same engine the product uses. Scoring here is deterministic rather than model-written, so this page costs nothing to run and nothing is saved. In a track built from your own posting, the same rubric is graded by the model, which is what produces feedback about your reasoning rather than about coverage.
This is the kind of first calculation almost every hardware intern is asked to do on day one before touching a real board.
You're wiring a simple LED indicator: a 5V supply, an LED with a 2V forward drop, and a series current-limiting resistor. If you use a 220-ohm resistor, calculate the current through the LED and state whether it falls in the typical 15-20mA safe range for a standard indicator LED.
This one resolves to a number. Give the value in the field below and your reasoning in the box — the number is checked exactly, by arithmetic.