物理 1996 年 DSE、CE 選擇題（第 2 頁）

11.

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

12.

Object O and image I at the same point in front of a convex lens and a plane mirror; distances 10 cm and 4 cm

When an object $O$ is placed in front of a convex lens and a plane mirror as shown above, an image $I$ is formed at the same position as the object. Which of the following statements is/are correct ?

(1)The image

I

is real.

(2)The focal length of the lens is

10

cm.

(3)If the distance between the lens and the plane mirror is changed to

2

cm, the position of the image

I

would remain unchanged.

13.

The temperature of two gases are $0^\circ$ C and $100^\circ$ C respectively. Express the temperature difference of the two gases in absolute temperature scale.

14.

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 ?

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

15.

Which of the following phenomena concerning water can be explained by its high specific heat capacity ?

(1)Water is used as a coolant in car engines.

(2)Inland areas generally have hotter summers and colder winters than coastal areas of similar latitude and altitude.

(3)The body temperature of human beings changes slowly even when the surrounding temperature changes sharply.

16.

Questions 22 and 23 : The following apparatus is used to find the specific latent heat of vaporization of a liquid.

Beaker of liquid with immersion heater connected to a power supply, standing on an electronic balance

When the liquid boils, the reading of the balance is taken. After $200$ s, the reading of the balance decreases by $0.02$ kg. The power output of the heater is $150$ W. If $20\%$ of the energy supplied is lost to the surroundings, find the specific latent heat of vaporization of the liquid.

17.

Questions 22 and 23 : The following apparatus is used to find the specific latent heat of vaporization of a liquid.

Which of the following can improve the accuracy of the experiment ?

(1)covering the beaker with a lid

(2)completely immersing the heating coil in liquid

(3)stirring the liquid throughout the experiment

18.

Temperature against time graphs for solids X and Y: X rises steeply with a short flat section, Y rises less steeply with a longer flat section at higher temperature

Two solids $X$ and $Y$ of equal mass are separately heated by two identical heaters. The above figure shows the variation of the temperatures of the substances with time. Which of the following statements is/are correct ?

(1)The melting point of

X

is higher than that of

Y

.

(2)The specific heat capacity of

X

is smaller than that of

Y

.

(3)The specific latent heat of fusion of

X

is smaller than that of

Y

.

19.

The volume of a fixed mass of gas is $V$ . If the pressure of the gas is doubled and its absolute temperature is reduced to half of the initial value, the volume of the gas becomes

20.

Which of the following descriptions concerning the gas molecules is correct when a fixed mass of gas is compressed and also heated at the same time ?

	Average spacing between the gas molecules	Average speed of the gas molecules
	remains unchanged	increases
	decreases	increases
	decreases	decreases
	decreases	remains unchanged