(A): Common emitter mode of a transistor is widely used
(R): Current gain, voltage gain, and power gain are maximum in C.E mode of a transistors.

Options

A. Both 'A' and 'R' are true and 'R' is the correct explanation of 'A'
B. Both 'A' and 'R' are true and 'R' is not the correct explanation of 'A'
C. 'A' is true and 'R' is false
D. 'A' is false and 'R' is true

Answer

To solve the question, we need to analyze the given assertion (A) and reason (R) statements regarding the common emitter (C.E) mode of a transistor.

### Step-by-Step Solution:

1. **Understanding the Assertion (A)**:
- The assertion states that "Common emitter mode of a transistor is widely used."
- This statement is **true** because the common emitter configuration is indeed one of the most commonly used transistor configurations in amplifiers due to its favorable characteristics.

**Hint**: Think about the applications of transistors and which configuration is preferred for amplification.

2. **Understanding the Reason (R)**:
- The reason states that "Current gain, voltage gain, and power gain are maximum in C.E mode of a transistor."
- This statement is also **true**. In the common emitter configuration, the transistor provides high current gain (β), high voltage gain (Av), and consequently high power gain (Pg). The power gain can be expressed as:
\[ \text{Power Gain} = \text{Current Gain} \times \text{Voltage Gain} \]
- Since both current gain and voltage gain are maximized in this mode, it follows that the power gain is also maximized.

**Hint**: Recall the definitions of current gain, voltage gain, and how they relate to power gain in transistor configurations.

3. **Linking Assertion and Reason**:
- The reason (R) provides a valid explanation for the assertion (A). The high gains in current, voltage, and power in the common emitter mode are the reasons why this configuration is widely used.

**Hint**: Consider how the characteristics of a transistor influence its practical applications.

4. **Conclusion**:
- Since both the assertion (A) and reason (R) are true, and R correctly explains A, we conclude that both statements are true and R is the correct explanation of A.

**Final Answer**: Both A and R are true, and R is the correct explanation of A.