物理光的反射和折射 DSE、CE 選擇題（第 3 頁）

21.

Photograph of a tree and its image on a calm water surface

The photograph shows the image of a tree formed by the surface of a pool of calm water. Which of the following phenomena explains the formation of the image ?

22.

Ray travelling vertically downward onto the slanted face of a right-angled glass prism

A ray of light travels in air and strikes a glass prism as shown above. Which of the following diagrams best shows the path of the ray ?

Four ray diagrams A to D through the glass prism

23.

Ray striking the slanted side of a parallelogram glass block

A ray of light travels in air and strikes a glass block as shown above. Which of the following diagrams best shows the path of the ray ?

Four ray diagrams A to D through the glass block

24.

Ray entering a right-angled glass prism with angles 43 and 47 degrees and emerging along the top edge

A ray of light enters a glass prism and travels along the path as shown above. Find the refractive index of the glass.

25.

Ray incident on a rectangular glass block at 50 degrees to the normal

A ray of light travels in air and strikes a rectangular glass block at an angle of incidence $50^\circ$ . The critical angle of the glass is $42^\circ$ . Which of the following diagrams best shows the path of the ray ?

Four ray diagrams A to D through a rectangular glass block

26.

Red and violet light entering a glass block containing a prism-shaped air cavity

A beam consisting of red and violet light travels in a glass block with an air cavity. The cavity is in the shape of a prism as shown above. Which of the following diagrams best shows the subsequent path of the beam ?

Four diagrams A to D of the emergent red and violet rays

27.

Which of the following phenomena is/are caused by the refraction of light ?

(1)If a man who is spear-fishing aims his spear at where the fish appears to be, he will miss it.

(2)A spectrum is formed when white light passes through a prism.

(3)A light ray is transmitted through a curved glass fibre.

28.

Which of the following phenomena involve(s) total internal reflection of light ?

(1)The sparkling of a diamond.

(2)The formation of a mirage.

(3)A ruler appearing bent when dipped in water.

29.

A ray of red light travels in air and strikes a triangular glass prism at an angle of incidence $45^\circ$ . The critical angle of red light for the glass is $42^\circ$ . Which of the following diagrams best shows the path of the ray ?

Four ray diagrams A to D through a triangular prism

30.

A ray of light travelling in air enters a semi-circular glass block as shown. Different values of the angle of incidence $\theta$ and the corresponding values of the angle of refraction $\phi$ are measured. Which of the below expressions represents the refractive index of the glass ?

$Ray in air entering a semi-circular glass block with angle of incidence theta and angle of refraction phi$