What value of resistance is required to drop 9 volts with a current of 10 milliamperes?

To determine the required resistance, you need to apply Ohm's Law, which states that Resistance (R) equals Voltage (E) divided by Current (I). The formula is commonly written as R = E / I. Before performing the calculation, you must ensure all values are in their base units. The current is provided as 10 milliamperes (mA). Because one milliampere is one-thousandth of an ampere, 10 mA must be converted to 0.010 amperes. Now, substitute the standard values into the formula: R = 9 volts / 0.010 amperes. This calculation yields exactly 900 ohms. A common error is ignoring the milliampere prefix, which leads to incorrect arithmetic and choosing a distractor with the wrong number of zeros.