How does effect size affect alpha?

Question

As the effect size increases the power of a hypothesis test also increases, but what happens to alpha?

Answer 1

The effect size does not change $\alpha$. The significance level $\alpha$ is determined before; usually $\alpha = 0.05$ is chosen. The significance level is the probability of rejecting a true null hypothesis. This does not depend on the effect size, as the effect size says something about what happens when the null hypothesis is not true.