Four equal resistors, each of resistance `10 Omega`, are connected as shown in the circuit diagram. The equivalent resistance between A and B is

Options

A. `5Omega`
B. `10 Omega`
C. 20 Omega`
D. `40 Omega`

Answer

To find the equivalent resistance between points A and B for the given circuit with four equal resistors of 10 ohms each, we can follow these steps:

### Step-by-Step Solution:

1. **Identify the Configuration of Resistors**:
- We have four resistors, each with a resistance of 10 ohms. The configuration of these resistors needs to be analyzed to determine how they are connected (series, parallel, or a combination).

2. **Analyze the Circuit**:
- According to the problem, there is a diode connected between points C and D. For the purpose of calculating the equivalent resistance, we can consider the diode as a short circuit (assuming it is forward-biased).

3. **Simplify the Circuit**:
- By short-circuiting the diode, we can simplify the circuit. This means that the resistors connected in parallel will be the ones we need to focus on.

4. **Calculate the Equivalent Resistance**:
- The two resistors in parallel can be calculated using the formula for equivalent resistance in parallel:
\[ R_{eq} = \frac{R_1 \times R_2}{R_1 + R_2} \]
- For two resistors of 10 ohms each:
\[ R_{eq1} = \frac{10 \times 10}{10 + 10} = \frac{100}{20} = 5 \, \text{ohms} \]
- Since there are two sets of these parallel resistors, we can calculate the equivalent resistance again for the second pair, which will also be 5 ohms.

5. **Combine the Results**:
- Now, we have two equivalent resistances of 5 ohms in series:
\[ R_{total} = R_{eq1} + R_{eq2} = 5 + 5 = 10 \, \text{ohms} \]

6. **Final Result**:
- Therefore, the equivalent resistance between points A and B is 10 ohms.

### Final Answer:
The equivalent resistance between A and B is **10 ohms**.