Question

At one point in the circuit, there is an LED and a resistor in parallel with one another. If you measure the voltage drop across the LED as 2.1 V and the current through the LED as 20 mA, you know: Group of answer choices a) The current through the resistor is 20 mA b) The voltage drop across the resistor is 2.1 V and its current is 20 mA c) The voltage drop across the resistor is 2.1 V nothing about the current through or voltage drop across the resistor.

Answer 1

C. The voltage drop across the resistor is 2.1V and nothing about the current through the resistor.

Step-by-step explanation:

When connected in parallel, voltage across the resistances are the same. So if 2.1V was dropped across the LED then 2.1V was also dropped across the resistor. However, this tells us nothing about the current through the resistor. We can find the current across the resistor if we know the resistance of the resistor, but that's about it.

If it were a series connection, then the current would have been the same, but the voltage drop were another story.