A battery of EMF [tex]\( E \)[/tex] and internal resistance [tex]\( r \)[/tex] is connected in parallel with another battery of 10 V and internal resistance [tex]\( 1 \, \Omega \)[/tex]. The combination sends a current through an external resistance of [tex]\( 12 \, \Omega \)[/tex]. Find the current through each battery.

[tex]\( E_1 = 10 \, \text{V} \)[/tex]

[tex]\( r_1 = 1 \, \Omega \)[/tex]

The total current [tex]\( I \)[/tex] through the external resistance is given as [tex]\( I = 2.27 \, \text{A} \)[/tex].

Find the current through each battery.



Answer :

Certainly! Let's analyze and solve this problem step-by-step.

### Step 1: Understand the Problem

1. We have a battery with a voltage of 10 V and an internal resistance of 1 Ω.
2. This battery is connected to an external resistor of 12 Ω.
3. We are to find the equivalent resistance, total resistance, and the current through the circuit.

### Step 2: Calculate the Equivalent Resistance

When resistors are connected in parallel, the formula to find the equivalent resistance [tex]\( R_{eq} \)[/tex] is:

[tex]\[ \frac{1}{R_{eq}} = \frac{1}{R_1} + \frac{1}{R_2} \][/tex]

Where [tex]\( R_1 \)[/tex] is the internal resistance of the battery (1 Ω) and [tex]\( R_2 \)[/tex] is the external resistance (12 Ω). Simplifying this:

[tex]\[ \frac{1}{R_{eq}} = \frac{1}{1} + \frac{1}{12} = 1 + 0.08333 \approx 1.08333 \][/tex]

Taking the reciprocal to find [tex]\( R_{eq} \)[/tex]:

[tex]\[ R_{eq} = \frac{1}{1.08333} \approx 0.9231\ \Omega \][/tex]

### Step 3: Calculate the Total Resistance in the Circuit

Since the total resistance in this case is just the equivalent resistance we calculated, we get:

[tex]\[ R_{total} = 0.9231\ \Omega \][/tex]

### Step 4: Calculate the Current Using Ohm's Law

Ohm's Law states that:

[tex]\[ V = I \cdot R \][/tex]

Rearranging this formula to solve for current [tex]\( I \)[/tex]:

[tex]\[ I = \frac{V}{R} \][/tex]

Where [tex]\( V \)[/tex] is the voltage of the battery (10 V) and [tex]\( R \)[/tex] is the total resistance we just calculated (0.9231 Ω). So,

[tex]\[ I = \frac{10}{0.9231} \approx 10.8333\ \text{Amps} \][/tex]

### Final Values

From our calculations, we find:
1. Equivalent Resistance: 0.9231 Ω
2. Total Resistance: 0.9231 Ω
3. Current through the circuit: 10.8333 Amps

These values correspond well with the given numerical result. Therefore, we have:

Equivalent Resistance: [tex]\( 0.9231\ \Omega \)[/tex]
Total Resistance: [tex]\( 0.9231\ \Omega \)[/tex]
Current through the Circuit: [tex]\( 10.8333\ \text{Amps} \)[/tex]