Two resistors of resistances 55Ω and 75Ω connected in series are connected to four cells, each of 1.5V and internal resistance 0.8Ω. If the cells are connected in series, calculate the current passing through the circuit.
Answer (1)
To find the current passing through the circuit with the given components, you need to first determine the total resistance and total voltage in the circuit.
Step 1: Calculate the total resistance in the circuit.
Since the resistors and cells are connected in series, you add their resistances together.
Resistor 1: R 1 = 55 Ω
Resistor 2: R 2 = 75 Ω
Each cell has an internal resistance of 0.8 Ω . With four cells, the total internal resistance is: R internal = 4 × 0.8 Ω = 3.2 Ω
The total resistance of the circuit is: R total = R 1 + R 2 + R internal = 55 Ω + 75 Ω + 3.2 Ω = 133.2 Ω
Step 2: Calculate the total voltage in the circuit.
Each cell has a voltage of 1.5 V . The total voltage for four cells in series is: V total = 4 × 1.5 V = 6 V
Step 3: Use Ohm's Law to calculate the current.
Ohm's Law states that the current I through a circuit is equal to the total voltage V divided by the total resistance R : I = R total V total
Substituting the known values: I = 133.2 Ω 6 V ≈ 0.045 A
Therefore, the current passing through the circuit is approximately 0.045 A .
