物理 2011 年 DSE、CE 選擇題（第 2 頁）

11.

The figure below shows a solar cooker. Which of the following statements about its design is incorrect ?

Solar cooker: sunlight onto a glass cover, board P reflecting, pot Q inside case R

12.

Compare the time taken for the following waves to travel a distance of $100$ m. $T_1$ Water waves with frequency $0.5$ Hz and wavelength $2$ m $T_2$ Sound waves travelling at $340\ \mathrm{m\,s^{-1}}$ $T_3$ Microwaves emitted by an artificial satellite The time taken in **descending** order is

13.

Photograph of a bird and its clear image on a calm water surface

A clear image of a bird is formed by a calm water surface as shown in the above figure. Which of the following statements about the image is/are correct ?

(1)The image is real.

(2)A clear image is formed as regular reflection occurs.

(3)If the bird is closer to the water surface, the size of the image increases.

14.

When a light ray travels from air to glass, which of the following descriptions about the changes of the speed, the frequency and the wavelength of the ray is correct ?

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

15.

An object is placed in front of a concave lens. Which of the following descriptions about the image formed by the lens is incorrect ?

16.

Object O and its upright image I on the principal axis, with points X and Y

The figure above shows an object $O$ and its image $I$ formed by a lens. Which of the following about the lens used and its position is correct ?

	Type of lens	Position of lens
	concave	$X$
	concave	$Y$
	convex	$X$
	convex	$Y$

17.

The figure below shows the current-voltage ( $I$ - $V$ ) graphs of two resistors $P$ and $Q$ .

I against V graph with two straight lines through the origin, P steeper than Q

Which of the following statements about the two resistors are correct ?

(1)Both of them obey Ohm's law.

(2)The resistance of

P

is greater than that of

Q

.

(3)If they are connected in parallel to a battery, the current passing through

P

will be greater than that passing through

Q

.

18.

Which of the following resistor networks gives the largest equivalent resistance across $PQ$ if all the resistors have the same resistance ?

Four ring-shaped resistor networks A to D with terminals P and Q: A has 2 resistors per side, B pentagon, C hexagon with P and Q adjacent, D hexagon with P and Q opposite

19.

Battery with 6 ohm resistor, ammeter, 6 ohm resistor, and 3 ohm resistor with switch S

In the circuit shown, the ammeter reading is $1.0$ A when $S$ is open. What is the ammeter reading when $S$ is closed ?

20.

Rectangular coil $PQRS$ is carrying a current flowing in clockwise direction. It is placed inside a uniform magnetic field pointing into the paper as shown in the figure above.

Rectangular coil PQRS in a uniform magnetic field into the paper, current clockwise

Which of the following statements are correct ?

(1)A magnetic force pointing to the right acts on

RS

.

(2)No magnetic force acts on

QR

.

(3)The resultant magnetic force acting on the coil is zero.