Why is it advisable to use a small value for the incidence angle when performing a glass prism experiment

Verified Answer :

FOCAL LENGTH = 9.5cm
i° e° d°

30 43 69
40 41 61
45 39 56
50 37 48
65 41 37
plot a graph of d° against i°
from the graph Determine;
(i) the minimum deviation and the corresponding angle of incidence
(ii) the maximum deviation and the corresponding angle of incidence
n=sin⁡(A+D÷2)÷(sinA÷2)
Determine the error in n and explain why it is not advisable to use small values of i° in performing this experiment.