Two cells of emf 1.5 volt and 2 volt and internal resitance 2 ohm and ...
Given information:
- Two cells with emf 1.5 V and 2 V
- Internal resistance of the cells: 2 ohm and 1 ohm
- Negative terminals of the cells are joined by a wire of 6 ohm
- Positive terminals of the cells are joined by a wire of 8 ohm
- The midpoints of these two wires are connected
Calculating the equivalent resistance:
To find the current and potential difference at the ends of the third wire, we need to calculate the equivalent resistance of the circuit.
1. Calculate the total resistance of the circuit:
- The internal resistance of the first cell is 2 ohm, and the wire resistance is 6 ohm, so the total resistance in that branch is 8 ohm.
- Similarly, the internal resistance of the second cell is 1 ohm, and the wire resistance is 8 ohm, so the total resistance in that branch is 9 ohm.
- Since the two branches are in parallel, we can calculate the total resistance using the formula: 1/Req = 1/R1 + 1/R2, where R1 = 8 ohm and R2 = 9 ohm.
- Solving the equation, we find Req = 4.5 ohm.
Calculating the current:
2. Calculate the total emf of the circuit:
- Since the emf of the first cell is 1.5 V and the emf of the second cell is 2 V, the total emf is the sum of these two: 1.5 V + 2 V = 3.5 V.
3. Calculate the current using Ohm's law:
- I = V/Req, where V is the total emf (3.5 V) and Req is the equivalent resistance (4.5 ohm).
- Solving the equation, we find I = 0.78 A (rounded to two decimal places).
Calculating the potential difference:
4. Calculate the potential difference at the ends of the third wire:
- Since the midpoints of the two wires are connected, the potential difference across the third wire is the same as the potential difference across the second wire.
- To calculate the potential difference across the second wire, we can use Ohm's law: V = I * R, where I is the current (0.78 A) and R is the resistance of the second wire (8 ohm).
- Solving the equation, we find V = 6.24 V (rounded to two decimal places).
Summary:
- The current in the circuit is 0.78 A.
- The potential difference at the ends of the third wire is 6.24 V.