Three resistors (15, 20, 25 ohms in this order) are connected to a 13-V battery . The internal resistance of the battery is negligible. What is the voltage difference across the 20-Ω resistance?
I=E/(R1+R2+R3)=13/(15+20+25)=0,217 Amps.
V = I*R2 = 0.217 * 20 = 4.33 Volts.
To determine the voltage difference across the 20-Ω resistance, we need to calculate the total resistance of the circuit and then use Ohm's Law.
First, we need to find the total resistance (R_total) in the circuit. In this case, the resistors are connected in series, so we can add up the resistances:
R_total = 15 Ω + 20 Ω + 25 Ω
R_total = 60 Ω
Next, we can use Ohm's Law (V = I * R) to calculate the current (I) in the circuit. Since the internal resistance of the battery is negligible and the resistors are connected in series, the current is the same throughout the circuit:
I = V / R_total
I = 13 V / 60 Ω
Now that we have the current, we can calculate the voltage difference across the 20-Ω resistor. Since the resistors are connected in series, the voltage drop across each resistor is proportional to its resistance. Therefore, the voltage difference across the 20-Ω resistor is:
V_20Ω = I * 20 Ω