物理光的波動性 DSE、CE 選擇題（第 3 頁）

21.

What happens to the wavelength and frequency of a ray of light if it passes from water to air ?

	Wavelength	Frequency
	increases	decreases
	decreases	remains unchanged
	remains unchanged	increases
	increases	remains unchanged

22.

Part of the electromagnetic spectrum: infra-red, P, Q, X-rays

The diagram shows part of the electromagnetic spectrum. Which of the following statements is/are true ?

(1)The wavelength of

P

is longer than that of

Q

.

(2)The velocity of

P

in a vacuum is smaller than that of

Q

.

(3)

Q

can be deflected by an electric field.

23.

A pulse of microwave of speed $3\times10^{8}\ \mathrm{m\,s^{-1}}$ is sent out to detect the position of a stationary weather balloon. The reflected microwave was picked up in $2\times10^{-4}$ s after emission. What is the distance of the balloon from the station ?

24.

Which of the following descriptions about the nature of light is/are correct ?

(1)The speed of light in a vacuum is independent of its wavelength.

(2)There cannot be total internal reflection when light is travelling from air to water.

(3)Light travels faster in glass than in air.

25.

Arrange the following in ascending order of wavelengths.

(1)X-rays

(2)Microwaves

(3)Visible light

(4)Ultra-violet rays

26.

Which of the following has the shortest wavelength ?

27.

Which of the following is/are transverse wave(s) ?

(1)water waves

(2)sound waves

(3)X-rays

28.

When light travels from air to glass, which of the following statements is/are true ?

(1)The speed of the light changes.

(2)The wavelength of the light increases.

(3)The frequency of the light remains unchanged.

29.

A short pulse of microwave travelling at $3\times10^{8}\ \mathrm{m\,s^{-1}}$ was used to detect the position of a stationary weather balloon. It was found that the microwaves reflected from the balloon were picked up $2\times10^{-4}$ s after the pulse had been emitted from the station. The distance of the balloon from the station was

30.

Which of the following is in the correct order of increasing wavelengths ?