A current of 2.0 ampere passes through a cell of e.m.f. 1.5 volts having internal resistance of 0.15 ohm. The potential difference measured, in volts, across both the ends of the cell will be

Options

A. `1.35`
B. `1.50`
C. `1.00`
D. `1.20`

Answer

To solve the problem, we will use the formula for the potential difference (V) across the terminals of a cell when a current is flowing through it. The formula is given by:

\[ V = E - I \cdot r \]

where:
- \( V \) is the potential difference across the terminals,
- \( E \) is the electromotive force (e.m.f.) of the cell,
- \( I \) is the current flowing through the cell,
- \( r \) is the internal resistance of the cell.

### Step-by-Step Solution:

1. **Identify the given values:**
- Electromotive force (e.m.f.), \( E = 1.5 \) volts
- Current, \( I = 2.0 \) amperes
- Internal resistance, \( r = 0.15 \) ohms

2. **Calculate the voltage drop across the internal resistance:**
- The voltage drop across the internal resistance can be calculated using the formula:
\[ \text{Voltage drop} = I \cdot r \]
- Substituting the values:
\[ \text{Voltage drop} = 2.0 \, \text{A} \cdot 0.15 \, \Omega = 0.3 \, \text{V} \]

3. **Calculate the potential difference across the terminals:**
- Now, we can find the potential difference across the terminals using the formula:
\[ V = E - I \cdot r \]
- Substituting the values:
\[ V = 1.5 \, \text{V} - 0.3 \, \text{V} = 1.2 \, \text{V} \]

4. **Conclusion:**
- The potential difference measured across both ends of the cell is \( 1.2 \) volts.

### Final Answer:
The potential difference across both ends of the cell is **1.2 volts**.

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