Four identical capacitors each rates as `10 mu F - 10V` are supplied to you to obtain capacitor of `10 mu F - 20 V`, we should connect them in

Options

A. two rows each containing 2 condensers
B. four rows each containing 1 condenser
C. one row containing four condensers
D. all the above

Answer

To solve the problem of obtaining a capacitor of 10 µF - 20 V using four identical capacitors rated at 10 µF - 10 V, we need to determine the correct configuration to achieve the desired capacitance and voltage rating.

### Step-by-Step Solution:

1. **Understanding the Capacitor Ratings**:
Each capacitor has a capacitance of 10 µF and a voltage rating of 10 V. We want to achieve a total capacitance of 10 µF and a voltage rating of 20 V.

2. **Voltage Requirement**:
To achieve a voltage rating of 20 V, we can connect capacitors in series. When capacitors are connected in series, the total voltage rating is the sum of the individual voltage ratings.

3. **Capacitance in Series**:
When capacitors are connected in series, the equivalent capacitance (C_eq) is given by the formula:
\[ \frac{1}{C_{eq}} = \frac{1}{C_1} + \frac{1}{C_2} + \ldots + \frac{1}{C_n} \]
For two capacitors in series, this simplifies to:
\[ C_{eq} = \frac{C}{n} \]
where n is the number of capacitors in series.

4. **Connecting Two Capacitors in Series**:
If we connect two capacitors in series, the equivalent capacitance will be:
\[ C_{eq} = \frac{10 \, \mu F}{2} = 5 \, \mu F \]
The voltage rating will be:
\[ V_{total} = 10 \, V + 10 \, V = 20 \, V \]

5. **Creating Two Sets of Series Capacitors**:
Now we can create two sets of these series capacitors. Each set will have an equivalent capacitance of 5 µF and a voltage rating of 20 V.

6. **Connecting the Two Sets in Parallel**:
If we connect these two sets of 5 µF capacitors in parallel, the equivalent capacitance will be:
\[ C_{eq} = 5 \, \mu F + 5 \, \mu F = 10 \, \mu F \]
The voltage rating remains at 20 V.

7. **Final Configuration**:
Therefore, the final configuration to achieve a capacitor of 10 µF - 20 V is to connect two rows, each containing two capacitors in series, and then connect these two rows in parallel.

### Conclusion:
The correct answer is to connect the capacitors in **two rows, each containing two capacitors in series**.