Answer :
Final answer:
The voltage reading on a voltmeter for the 100 ohm resistor in a series circuit with a total resistance of 300 ohms and a 12V battery is 4 volts. B. 4 V
Explanation:
The student's question pertains to the voltage reading on a voltmeter when connected to a circuit with two resistors of known values and a given battery voltage. To find the voltage across one of the resistors, we must determine the total resistance of the circuit and calculate the current. The total resistance in series is the sum of the individual resistances, so in this case, it's 100 ohm + 200 ohm = 300 ohm. The current (I) in the circuit using Ohm's law (V=IR) is I = V/R, which is I = 12V / 300 ohm = 0.04 A. Now, to find the voltage across the 100 ohm resistor, again we use Ohm's law, V = IR, which gives us V = 0.04 A * 100 ohm = 4V. Therefore, the reading on the voltmeter across the 100 ohm resistor would be 4 volts, so the answer is B. 4V.
