In a transistor if $\frac{I_C}{I_E}=\alpha$ and $\frac{I_C}{I_B}=\beta$. If $\alpha$ varies between…

In a transistor if $\frac{I_C}{I_E}=\alpha$ and $\frac{I_C}{I_B}=\beta$. If $\alpha$ varies between $\frac{20}{21}$ and $\frac{100}{101}$, then the value of $\beta$ lies between
  1. $1-10$
  2. $0.95-0.99$
  3. $20-100$
  4. $200-300$

Solution

$\beta=\frac{\alpha}{1-\alpha}$ $\beta_1=\frac{\frac{20}{21}}{1-\frac{20}{21}}=20, \quad \beta_2=\frac{\frac{100}{101}}{1-\frac{100}{101}}=100$ The value of $\beta$ lies between $20-100$.

Asked in: AP EAMCET 2012

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