There are five equal resistors. The minimum resistance possible by their combination is 2 ohm. The maximum possible resistance we can make with them is

Options

A. 25 ohm
B. 50 ohm
C. 100 ohm
D. 150 ohm

Explanation

To solve the problem, we need to determine the maximum resistance that can be achieved by combining five equal resistors, given that the minimum resistance possible is 2 ohms.

### Step-by-Step Solution:

1. **Understanding Minimum Resistance**:
The minimum resistance occurs when all resistors are connected in parallel. The formula for the equivalent resistance \( R_{eq} \) for \( n \) resistors of equal resistance \( R \) in parallel is given by:
\[ R_{eq} = \frac{R}{n} \]
For 5 resistors, this becomes:
\[ R_{eq} = \frac{R}{5} \]
We know from the problem that the minimum resistance is 2 ohms:
\[ \frac{R}{5} = 2 \implies R = 10 \text{ ohms} \]

2. **Finding Maximum Resistance**:
The maximum resistance occurs when all resistors are connected in series. The formula for the equivalent resistance \( R_{eq} \) for \( n \) resistors of equal resistance \( R \) in series is:
\[ R_{eq} = nR \]
For 5 resistors:
\[ R_{eq} = 5R \]
Substituting the value of \( R \) we found:
\[ R_{eq} = 5 \times 10 = 50 \text{ ohms} \]

3. **Conclusion**:
Therefore, the maximum possible resistance that can be achieved by combining the five equal resistors is:
\[ \boxed{50 \text{ ohms}} \]