The formula for the critical angle is:
sin (critical angle) = refractive index of solution / refractive index of air
=> refractive index of solution / refrative index of air = sin (48°)
=> refractive index of solution / refractive index of air = 0.7431
=> refractive index of solution = 0.7431 * refractive index of air
=> refractive index of solution = 0.7431 * 1.00
=> refractive index of solution = 0.74
Answser: 0.74
