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.