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Free calculations lesson

Calculate current, voltage, and resistance.

Question 1 of 4

A 30 Ω resistive load is connected to 240 V. How much current does it draw?

A0.125 A
B7,200 A
C8 ACorrect answer
D210 AYour answer

Incorrect. You chose D. The correct answer is C: 8 A.

210 comes from subtracting 30 from 240. Ohm's law uses division to find current: I = E ÷ R = 240 ÷ 30 = 8 A.

Check the method

Try a fresh problem using the same method. It does not count toward your score.

A resistor carries 4 A when 48 V is applied. The voltage is then raised until the resistor carries 6 A. What voltage is now applied? (The resistance does not change.)

Skip the check and go to the next question