Question

If the current constant for a transistor are α and β then :-
(a)αβ=1 (b)β>1,α<1
(c)α=β. (d)β<1,α>1

Answer 1

ans: (b) α < 1 , β > 1 



Alpha ( α ) : it is the ratio of collector current variations to emitter current variations. when no load and voltage be constant. 
e.g., α = Ic/Ie 
where , Ic is collector current variations 
Ie is the emitter current variations 

similarly, 
Beta ( β ) : it is the ratio of collector current variations to base current variations on no load and constant voltage. 
e.g., β = Ic/Ib 

now, the relationship between alpha and beta 
$\beta=\frac{\alpha}{1-\alpha}$
$or, \alpha=\frac{\beta}{\beta+1}$


from above relation it is clear that , 
α < 1 and β > 1 

Answer 2

Answer is : option B 

Explanation :
Alpha [α] is the ratio of collector current and emitter current

α=collector current/emitter current

α =IC/IE

Its value is less than 1

β is the ratio of collector current and base current.

β=Ic/Ib
Its value is greater than 100.

Relation between  α and β

β=α/1-α
α=β/β+1
Conclusion:α<1 and β>1