Final answer:
When exposure has no effect on the health outcome, the expected value of Relative Risk is 1, indicating no association between exposure and outcome.
Step-by-step explanation:
If the exposure has no effect, then the expected value of Relative Risk (RR) is 1. This happens because the incidence of the outcome in the exposed group would be the same as the incidence in the non-exposed group. Since RR is calculated by dividing the incidence in the exposed group by the incidence in the non-exposed group, if these are equal, the quotient is 1, indicating no association between the exposure and the outcome.