Given $\beta = 50$. we need to calculate the ratio of change in collector current to the change in emitter current which is nothing but $\alpha$.

For a transistor, the relationship between $\alpha$ and $\beta$ is as follows: $\beta = \large\frac{I_c}{I_B}$ and $\alpha = \large\frac{I_C}{I_E}$, hence $\large\frac{\beta}{\alpha} $$=\large \frac{I_E}{I_B}$

$I_B = I_E - I_C \rightarrow \large\frac{\beta}{\alpha} $$ = \large\frac{1}{1 - \alpha} $$ \rightarrow \beta = \large\frac{\alpha}{1-\alpha}$

$\Rightarrow 50 =\large\frac{ \alpha}{1- \alpha}$

$\quad 50 -50 \alpha= \alpha$

$\Rightarrow \alpha =\large\frac{50}{51}$

$\qquad= 0.98$