Calculate the total resistance of a circuit with a 6V EMF source, 0.5 Ohm internal resistance, and resistors R1=2 Ohm, R2=2 Ohm, R3=3 Ohm, R4=2 Ohm when the switch is closed.

Here are the solutions to the circuit problems:

Given values:

• Electromotive force (EMF) of the source, $\mathcal{E} = 6 \, \text{V}$
• Internal resistance of the source, $r = 0.5 \, \Omega$
• Resistance $R_1 = 2 \, \Omega$
• Resistance $R_2 = 2 \, \Omega$
• Resistance $R_3 = 3 \, \Omega$
• Resistance $R_4 = 2 \, \Omega$

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I. Total resistance of the circuit when the switch is closed.

Step 1: Analyze the circuit when the switch is closed.
When the switch is closed, it creates a