Ce Phy Mock Paper D1

KWOK TAK SENG CATHOLIC SECONDARY SCHOOL S.5 MOCK EXAMINATION 2004-05

Name

PHYSICS PAPER I Question/Answer Book

Class Class No.

7 - 3 -2005 Time allowed : 1 34 hours Total no. of pages : 14 This paper must be answered in English

Marks INSTRUCTIONS 1.

Write your Name, Class and Class Number in the spaces provided on this cover.

2.

This paper consists of TWO sections, Section A and Section B. Section A carries 54 marks and Section B carries 36 marks. Answer ALL questions in each section. Write your answers in the spaces provided in this QuestionAnswer Book. Supplementary answer sheets will be supplied on request. Write your Class and Class Number on each sheet and fasten them with string inside this book. Some questions contains parts marked with an asterisk (*). In answering these parts, candidates are required to give paragraph-length answers. In each of these parts, one mark is allocated to assess candidates’ ability in effective communication. Unless otherwise specified, numerical answers should be either exact or correct to 3 significant figures. Take g = 10 m s-2 . Unless otherwise specified, all the cells are assumed to have negligible internal resistance.

3.

4.

5.

6. 7.

1 2 3 4 5 6 7 8 9 10 11

Total

S.5/PHY-I/P.2

Useful Formulae in Physics

(a) Relationships between initial velocity u, uniform acceleration a, final velocity v and displacement travelled s after time t : v = u + at 2 s = ut + 21 at 2

v =u

2

+ 2 as

(b) Potential energy gained by a body of mass m when raised through a height h is mgh. (c) Kinetic energy of a body of mass m moving with speed v is

1 2

mv2

(d) Power = force × velocity (e) Equivalent resistance of two resistors R1 and R2 : (i) in series = R1 + R2 (ii)

in parallel =

R1 R2 R1 + R2

(f) Power = potential difference × current

SECTION A (54 marks) Answer ALL questions in this section and write your answers in the spaces provided.

1.

Question No.

1

2

3

4

5

6

7

8

Marks

5

5

11

5

7

6

6

9

A water wave of frequency 80 Hz is travelling from left to right on the water surface in a glass ripple tank. The above diagram shows a snap-shot of the wave at a certain instant. A cork is placed at point R.

(a)

Describe the subsequent motion of the cork.

(1 mark) _______________________________________________________________________ _ _______________________________________________________________________ _

S.5/PHY-I/P.3

(b)

Find the wave velocity of the water wave.

(2 marks) _______________________________________________________________________ _ _______________________________________________________________________ _ _______________________________________________________________________ _ _______________________________________________________________________ _ (c) Give two methods to increase the wavelength of the water wave. (2 marks) _______________________________________________________________________ _ _______________________________________________________________________ _ _______________________________________________________________________ _ _______________________________________________________________________ _

2.

In Figure 7.72, Tom is looking at some small print on a piece of paper. Meanwhile, he moves a glass block of uniform thickness 3 cm over the print. Then the print appears to rise by 0.9 cm.

(a)

Draw a ray diagram to show how Tom views the print through the glass block. (2 marks)

(b)

What is the nature of the image? (1 mark)

S.5/PHY-I/P.4

_______________________________________________________________________ _ (c) Comment on and explain any changes of the image if the glass block is replaced by a tank of water with a depth of 3 cm. (2 marks) _______________________________________________________________________ _ _______________________________________________________________________ _ _______________________________________________________________________ _ _______________________________________________________________________ _

S.5/PHY-I/P.5

3.

A small block of mass 3 kg is projected up a rough slope as shown in Figure 3.62. It eventually stops at point B and stays there. Figure 3.63 shows the speed of the block during the uphill journey. Hint : The friction between the block and the slope remains unchanged.

(a)

Find the value of d.

(2 marks) _______________________________________________________________________ _ _______________________________________________________________________ _ (b) Find the acceleration of the block. (2 marks) _______________________________________________________________________ _ _______________________________________________________________________ _ (c) Draw a force diagram of the block (i) while the block is moving up the slope; and (3 marks)

(ii)

when the block remains at rest at B. (1 mark)

(d)

Find the frictional force acting on the block.

(3 marks) _______________________________________________________________________ _ _______________________________________________________________________ _

S.5/PHY-I/P.6

_______________________________________________________________________ _ _______________________________________________________________________ _ _______________________________________________________________________ _ _______________________________________________________________________ _ _______________________________________________________________________ _ _______________________________________________________________________ _

S.5/PHY-I/P.7

4.

There are two ways to store microchips properly: to put them in conductive envelopes and to insert them into a foam board with aluminium foil attached. conductive envelope

aluminium foil

foam board

(a)

If a microchip is stored properly in a conductive envelope, is it possible to have some of its terminals charged and some uncharged? Explain briefly. (3 marks) _______________________________________________________________________ _ _______________________________________________________________________ _ _______________________________________________________________________ _ _______________________________________________________________________ _ _______________________________________________________________________ _ _______________________________________________________________________ _ _______________________________________________________________________ _ _______________________________________________________________________ _ (b) It is known that microchips are easily damaged by sparks. Explain why it is appropriate to store microchips in a conductive envelope. (2 marks) _______________________________________________________________________ _ _______________________________________________________________________ _ _______________________________________________________________________ _ _______________________________________________________________________ _ _______________________________________________________________________ _ _______________________________________________________________________ _

S.5/PHY-I/P.8

5.

Mary sets up a circuit as shown in the following figure to find out how the voltage across a light bulb relates to the current passing through it.

S.5/PHY-I/P.9

(a)

Mary has made a mistake in connecting the circuit. What is the mistake?

(1 mark) _______________________________________________________________________ _ _______________________________________________________________________ _ (b) After fixing the mistake, Mary carries out the experiment and obtains the following results: Voltage across the bulb (V) / V

1.0

1.8

2.8

4.0

5.0

6.4

Current through the bulb (I) / A

0.3

0.6

0.9

1.3

1.6

1.9

(i)

Plot a graph of V against I on graph paper. (4 marks)

(ii)

Explain why the graph is not a straight line.

(2 marks) _________________________________________________________________ _ _________________________________________________________________ _ _________________________________________________________________ _ _________________________________________________________________ _

S.5/PHY-I/P.10

6.

The adaptor in the following figure is used to charge batteries of mobile phones. Input: 220 V ~ / 50 Hz / 24 mA Output: 6 V / 150 mA

(a)

Explain briefly why the plug has an earth pin even though it is made of plastic. (1 mark) _______________________________________________________________________ _ _______________________________________________________________________ _ (b)

Calculate the input and output power of the adapter with the information on the label. Hence, find the percentage of useful input power. (4 marks) _______________________________________________________________________ _ _______________________________________________________________________ _ _______________________________________________________________________ _ _______________________________________________________________________ _ _______________________________________________________________________ _ _______________________________________________________________________ _ _______________________________________________________________________ _ _______________________________________________________________________ _ _______________________________________________________________________ _ _______________________________________________________________________ _ (c)

What happens to the difference between input and output power?

(1 mark) _______________________________________________________________________ _ _______________________________________________________________________ _

S.5/PHY-I/P.11

7.

Figure a shows a toy, magna doodle, which has a pen for writing on the display and a “duster” for clearing the display. display

slider of the duster pen Figure a

S.5/PHY-I/P.12

The display of the doodle has three layers (Fig b). The front and the back layers are transparent plastic sheets. The middle layer is a layer of hexagonal plastic lattice. Each cell of the lattice is filled with a thick white liquid and tiny dark iron particles. front cell of the lattice filled

transparent

with thick white liquid

plastic sheets

and tiny dark iron back

particles

Figure b

(a)

The display is white in the beginning. What can be seen on the display when a magnet is put on it? Explain briefly (2 marks) _______________________________________________________________________ _ _______________________________________________________________________ _ _______________________________________________________________________ _ _______________________________________________________________________ _ (b)

From (a), (i) what should be put at the tip of the pen, so that it can write on the display? (1 mark) (ii) where should the “duster” be? And what is its working principle? (3 marks) _______________________________________________________________________ _ _______________________________________________________________________ _ _______________________________________________________________________ _ _______________________________________________________________________ _ _______________________________________________________________________ _ _______________________________________________________________________ _ _______________________________________________________________________ _ _______________________________________________________________________ _ _______________________________________________________________________ _

S.5/PHY-I/P.13

_______________________________________________________________________ _

S.5/PHY-I/P.14

8. Radioactive iodine Small doses of radioactive iodine can be used to help diagnose cancer of the thyroid. When given in larger doses , radioactive iodine can be used to treat any remaining cancer cells . Radioactive iodine is only us eful for the detection and treatm ent of any cancer cells that may remain once all of the healthy thyroid tiss ue has been removed. The radioactive su bs tance used for treatm ent is the sam e as that used for radioisotope scanning, bu t is given in m uch larger doses . It is eith er ta ken as a drink or in capsule form, or injected into a vein in the arm. It is a way of giving radiotherapy internally, rather than externally in the form of high-energy rays . The thyroid cancer cells absorb the iodine and receive a very high dose of radiation, which will help to destroy them . Radioactive iodine has very little effect on other parts of the body s ince other cells do not absorb iodine as m uch as the thyroid cells . Radioactive iodine treatment can be repeated if further tes ts show that there are cancer cells left.

(a)

129 131 Iodine-123 ( 123 53 I) , iodine-129 ( 53 I) and iodine-131 ( 53 I) are radioactive isotopes

of iodine. I-123 has a half-life of 13.3 hours, I-129 has a half-life of 15.7 million years and I-131 has a half-life of about 8 days. All of them emit beta particles upon radioactive decay. (i) Write a decay equation for I-129. Use “X” as the atomic symbol of the daughter nuclide for the decay process. (1 mark) _________________________________________________________________ _ (ii) Which isotope is most suitable to be used in healing thyroid cancer? Explain briefly. (3 marks) _________________________________________________________________ _ _________________________________________________________________ _ _________________________________________________________________ _ _________________________________________________________________ _ _________________________________________________________________ _ _________________________________________________________________ _ (b)

When radiotherapy is given externally, which kind(s) of radioactive source should not be used? Explain briefly. (2 marks) _______________________________________________________________________ _

S.5/PHY-I/P.15

_______________________________________________________________________ _ (c)

Why radioactive isotope of iodine is suitable for healing thyroid cancer?

(3 marks) _______________________________________________________________________ _ _______________________________________________________________________ _ _______________________________________________________________________ _ _______________________________________________________________________ _

S.5/PHY-I/P.16

SECION B (36 marks) Answer ALL questions in this section and write your answers in the spaces provided.

9.

Question No.

9

10

11

Marks

13

9

14

A white ball is shot towards a stationary red ball by a cue as shown below. The cue pushes the white ball from rest with a constant force of 80 N for a distance of 0.5 cm. The white ball moves along to hit the red ball. Mass of the white ball and the red ball are 250 g and 350 g respectively.

(a)

Find the work done by the cue. (2 marks)

(b) (c)

(d)

(e)

Find the velocity of the white ball just before hitting the red ball. (2 marks) After impact, the red ball moves off with speed of 10 m s-1. What is the final velocity of the white ball? (3 marks) If the impact lasts for 0.04 s, what will be the average force acting on the red ball? (3 marks) In this kind of collison, 80% of the K.E. lost is converted to sound. The rest of K.E. lost is converted to another form. State the name of this form and calculate the amount of energy converted to this form. (3 marks)

_______________________________________________________________________ _ _______________________________________________________________________ _ _______________________________________________________________________ _ _______________________________________________________________________ _ _______________________________________________________________________ _ _______________________________________________________________________ _ _______________________________________________________________________ _ _______________________________________________________________________ _ _______________________________________________________________________ _

S.5/PHY-I/P.17

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S.5/PHY-I/P.18

_______________________________________________________________________ _ _______________________________________________________________________ _ _______________________________________________________________________ _ _______________________________________________________________________ _ _______________________________________________________________________ _ _______________________________________________________________________ _ _______________________________________________________________________ _ _______________________________________________________________________ _ _______________________________________________________________________ _ _______________________________________________________________________ _ _______________________________________________________________________ _ _______________________________________________________________________ _ _______________________________________________________________________ _ _______________________________________________________________________ _ _______________________________________________________________________ _ _______________________________________________________________________ _ _______________________________________________________________________ _ _______________________________________________________________________ _ _______________________________________________________________________ _ _______________________________________________________________________ _ _______________________________________________________________________ _ _______________________________________________________________________ _ _______________________________________________________________________ _

S.5/PHY-I/P.19

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S.5/PHY-I/P.20

10. A student performs an experiment to measure the specific heat capacity of a liquid. He uses an electric heater to supply energy to the liquid. The following circuit diagram shows how the current through the heating wire and the potential difference across it are measured. The power of the heating wire is then calculated from the meter readings. The meter readings are 500 mA and 12 V.

(a) (b)

Find the resistance of the heating wire. (2 marks) The heating wire is then immersed completely in the liquid as shown below. The mass of the liquid is 0.4 kg. The current is switched on for 30 minutes and the temperature of the liquid increases from 25°C to 37°C.

(i)

What is the function of the piece of cork? (2 marks)

(ii)

Find the energy supplied to the liquid. (2 marks)

(iii)

Calculate the specific heat capacity of the liquid. (3 marks)

_______________________________________________________________________ _ _______________________________________________________________________ _ _______________________________________________________________________ _ _______________________________________________________________________ _ _______________________________________________________________________ _ _______________________________________________________________________ _ _______________________________________________________________________ _ _______________________________________________________________________ _ _______________________________________________________________________ _

S.5/PHY-I/P.21

_______________________________________________________________________ _ _______________________________________________________________________ _ _______________________________________________________________________ _ _______________________________________________________________________ _ _______________________________________________________________________ _ _______________________________________________________________________ _ _______________________________________________________________________ _ _______________________________________________________________________ _

S.5/PHY-I/P.22

11.

Mary has a set of Christmas tree lights as shown in the following figure. The set of lights consists of twenty light bulbs rated at “11 V, 6 W” connected in series to the 220 V mains. 220 V

~

(a)

Find (i)

the current passing through the bulbs, (2 marks)

(ii) (b)

* (c)

(d)

the resistance of each bulb.

(2 marks) If the filament in one of the bulbs breaks, then all bulbs go out. Explain why this happens. (2 marks) Mary purchases another set of lights identical to the one above. How does the brightness of the light bulbs change if she connects two sets of lights in series and in parallel? Explain your answer. (6 marks) Some manufacturers use light bulbs as shown in the following figure for Christmas tree lights. These light bulbs have resistors and filaments connected in parallel.

What is the purpose of the resistor in the light bulb? Explain your answer. (2 marks)

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S.5/PHY-I/P.23

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S.5/PHY-I/P.24

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S.5/PHY-I/P.25

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END OF PAPER