物理 2000 年 DSE、CE 選擇題（第 2 頁）

11.

Concave lens with foci F and F', incident ray AB and possible emergent rays P, Q, R and S

In the above figure, $F$ and $F'$ are the foci of the above lens and $AB$ is an incident ray. Which of the following paths best represents the emergent ray ?

12.

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.

13.

Equal amount of four different liquids are separately heated at the same rate. The initial temperatures of the liquids are all $20^\circ\mathrm{C}$ . The boiling points and specific heat capacities of the liquids are shown below. Which one of the following liquids will boil first ?

Liquid	Boiling point / $^\circ$ C	Specific heat capacity / $\mathrm{J\,kg^{-1}\,{}^\circ C^{-1}}$
$P$	50	1000
$Q$	60	530
$R$	80	850
$S$	360	140

14.

Beaker of water with immersion heater connected to joulemeter and power supply, standing on an electronic balance

The above apparatus is used to find the specific latent heat of vaporization of water, $\ell_v$ . Which of the following factors will cause the result obtained to be larger than the true value of $\ell_v$ ?

(1)Some energy is lost to the surroundings.

(2)Some steam condenses and drips back into the beaker.

(3)Some boiling water inside the beaker splashes out of the beaker.

15.

An object $P$ has a higher temperature than another object $Q$ . Which of the following statements is/are correct ?

(1)The internal energy of

P

must be higher than that of

Q

.

(2)The specific heat capacity of

P

must be higher than that of

Q

.

(3)There will be a heat flow from

P

to

Q

when they are in contact.

16.

P-V graph: curve C with points X, Y and Z joined by the path X to Y (horizontal), Y to Z (vertical), Z to X along the curve

The curve $C$ in the graph shows the $P$ - $V$ relation of a fixed mass of ideal gas at a certain temperature. Point $X$ denotes the initial state of the gas. The state of the gas is now changed along the path shown from $X$ to $Y$ , then from $Y$ to $Z$ , and finally from $Z$ back to $X$ along the curve $C$ . Which of the following statements is/are correct ?

(1)The temperature of the gas remains unchanged in the transition from

X

to

Y

.

(2)The temperature of the gas decreases in the transition from

Y

to

Z

.

(3)The temperature of the gas remains unchanged in the transition from

Z

to

X

.

17.

Which of the following statements correctly describe(s) the meaning of the frequency of a wave ?

(1)the time taken for the wave to make one complete vibration

(2)the distance travelled by the wave in one second

(3)the number of waves produced in one second

18.

Scientists have discovered that ozone molecules in the earth's atmosphere are being destroyed. Which of the following electromagnetic waves is mainly responsible for causing hazard to human health as a result of the damaging of the ozone layer ?

19.

A water wave of frequency $30$ Hz travels in a deep region of water. When the wave enters a shallow region, its wavelength is reduced to one-third of its original value. Find the frequency of the water wave in the shallow region.

20.

Pulse PQ travelling towards a V-shaped barrier in a ripple tank

A straight pulse $PQ$ travels towards a $V$ -shaped barrier in a ripple tank as shown above. Which of the following diagrams best shows the reflected pulse(s) ?

Four diagrams A to D of reflected pulses at a V-shaped barrier