急! 急! 物理 - 折射光速度問題.

Q: 請問下圖的X定Y的折射率較高? Refractive index(折射率) n is defined as,n = sin(i)/sin(r )where I and r are the angle of incident (入射角) and angle of refraction (折射角) For light ray X, n(x) = sin(x)/sin(r)where x is the angle of incident for light ray XFor light ray Y, n(y) = sin(y)/sin( r)But it can be seen easily on the diagram that angle x > angle y, i.e. sin(x) > sin(y)Because, after refraction, both rays are parallel, refraction angles r are equalHence, n(x) > n(y) Q: X定Y的傳播速度較快? Refractive index n = speed of light in vacuum/speed of light in mediumThat is, speed of light in medium is inversely proportional to the refractive indexBecause, n(x) > n(y)This implies that: speed of light X in medium < speed of light Y in medium

假設X為1，Y為2
n1sinx1=n2sinx2
sinx1/sinx2=v1/v2
換句話說：
因為我地要由角度x出發，所以由x開始判斷
x↑--->sinx↑--->n↓&v↑
所以
入射角X>Y--->sinx>siny--->nx<ny&vx>vy