Semiconducting Devices Junction Transistor Question 44
Question: In the study of transistor as an amplifier, if $ \alpha =I_{c}/I_{e} $ and $ \beta =I_{c}/I_{b}, $ where $ I_{c},I_{b} $ and Ie are the collector, base and emitter currents, then [CBSE PMT 2000; KCET 2000; Orissa JEE 2005]
Options:
A) $ \beta =\frac{1-\alpha }{\alpha } $
B) $ \beta =\frac{\alpha }{1-\alpha } $
C) $ \beta =\frac{\alpha }{1+\alpha } $
D) $ \beta =\frac{1+\alpha }{\alpha } $
Answer:
Correct Answer: B
Solution:
As we know $ i_{E}=i_{C}+i_{B} $
$ \Rightarrow \frac{i_{e}}{i_{c}}=1+\frac{i_{b}}{i_{c}} $
$ \Rightarrow \frac{1}{\alpha }=1+\frac{1}{\beta } $
$ \Rightarrow \beta =\frac{\alpha }{1-\alpha } $ .
BETA
