Answer:
D. 1.7
Step-by-step explanation:
Refractive index can be calculated using the formula;
η =real depth/apparent depth
Assume the real depth to be-----x
Apparent depth will be : 40% less than real depth;
60/100 *x =0.6x
η = x/ 0.6 x
η = 1/0.6
η= 10/6
η = 1.66
η = 1.7