Question

angel of incedence	angle of reflection		average angle of reflection
	clockwise	counterclockwise
10	10	10	10
20	20	20	20
30	30	30	30
40	40	40	40
50	50	50	50
60	60	60	60
70	70	70	70
80	80	80	80
	acrylic lens			Glass lens
angel of incedence	angle of reflection		average angle of reflection	angle of reflection		average angle of reflection
	clockwise	counterclockwise		clockwise	counterclockwise
10	8	5	6.5	7	7	7
20	15	12	13.5	13	13	13
30	21	18	19.5	20	20	20
40	27	25	26	25	25	25
50	32	30	31	31	31	31
60	37	35	36	35	35	35
70	40	38	39	38	38	38
80	43	40	41.5	40	40	40

acrylic	glass	unknown fluid
Slope from the graph	Slope from the graph	Slope from the graph
index of refraction n=	index of refraction n=	index of refraction n=
%error=	%error=	%error=
critical angle	critical angle	critical angle
index of refraction n=	index of refraction n=	index of refraction n=
%error=	%error=	%error=

Answer 1

NOTE: 1st graph plot is for acrylic, 2nd is for glass. The slope are shown in graph itself. No plot for unknown sample is needed as it is clear that slope=1.