In a transistor, the value of `alpha=0.9`. Then the value of `beta` is:

Options

A. 1
B. 0.09
C. 0.9
D. 9

Answer

To find the value of beta (β) given that alpha (α) is 0.9 in a transistor, we can use the relationship between alpha and beta. The formula that relates alpha and beta is:

\[ \beta = \frac{\alpha}{1 - \alpha} \]

### Step-by-step Solution:

1. **Identify the given value of alpha (α)**:
- We have α = 0.9.

2. **Substitute the value of alpha into the formula**:
- Using the formula, we substitute α:
\[ \beta = \frac{0.9}{1 - 0.9} \]

3. **Calculate the denominator**:
- Calculate \(1 - 0.9\):
\[ 1 - 0.9 = 0.1 \]

4. **Substitute the denominator back into the equation**:
- Now we have:
\[ \beta = \frac{0.9}{0.1} \]

5. **Perform the division**:
- Calculate \(0.9 \div 0.1\):
\[ \beta = 9 \]

6. **Conclusion**:
- Therefore, the value of beta (β) is 9.

### Final Answer:
\[ \beta = 9 \]