Kwun Tong Government Secondary School s2

KWUN TONG GOVERNMENT SECONDARY SCHOOL SECOND TERM TEST, 2003-2004 Form Two Integrated Science Class : S.2 ( ) Date : 3-5-2004 Name : ______Time : 8:35-9:05am Class No.: ______Full Mark : 50

ANSWER ALL THE QUESTIONS ON THE ANSWER SHEET PROVIDED

(A) Multiple Choice (10 marks) 1. What does the following circuit symbol represent?

A. Fuse B. Light bulb C. Resistor D. Switch

2. Two identical resistors are connected in series. If the current flowing through point X is 0.1 A, what is the current flowing through point Y?

A. 0.05 A B. 0.1 A C. 0.2 A D. 0.4 A

3. Normally every wire has a resistance, though very small. This causes an energy loss during transfer, as electrical energy changes into A. sound energy. B. potential energy. C. heat energy. D. chemical energy.

4. Which resistor in the following circuit draws the largest current?

A. X B. Y C. Z D. All are the same

5. Label the holes X, Y and Z.

X Y Z X Y Z A. Live Earth Neutral B. Live Neutral Earth C. Earth Live Neutral D. Earth Neutral Live

6. Which of the following can indicate the pH value of a solution? A. Universal indicator B. Ammonia solution C. Red cabbage extract D. Litmus solution

7. Which of the following is a short circuit?

8. Which of the following parts of our body produces acid? A. Eyes B. Lungs C. Mouth D. Stomach

9. Which of the following statements about pH scale are correct? I It values from 1 to 14. II The pH value of a neutral solution is 7. III pH value 14 indicates strong acid. A. I and II only B. I and III only C. II and III only D. All of them

10. Which of the following parts of the eye help(s) focus light onto the retina? I Cornea II Optic nerve III Lens IV Pupil A. III only B. IV only C. I and III only D. I, II and IV only

(B) True or False Statements (5 marks) Write ‘T’ for a true statement and ‘F’ for a false one. 1. The current flows through a short circuit is larger, because the distance it travels becomes shorter. 2. A fuse should be connected to live wire. 3. Using ring mains circuit can prevent overloading. 4. A chemical with higher pH value is more acidic. 5. Blind spot has no light sensitive cells.

(C) Matching (5 marks) Column A Column B 1. Live wire A. A material that electric current cannot pass through 2. Conductor B. A material that electric current can pass through 3. Fuse C. An example of alkali 4. Calcium oxide D. An example of acid 5. smell E. Blue F. Brown G. A short piece of metal wire that will melt if the current is too large H. Nose I. Tongue

(D) Fill in the blanks (10 marks) 1. An ammeter is connected up in (a) ______to measure the (b) ______. 2. (c) ______is the opposition to the flow of the electric charges. Its unit is (d) _____. 3. A (e) ______has a variable resistance. Volume control is an example that makes use of it. 4. The reaction between an acid and an alkali is called (f) . In this reaction, (g) and (h) are produced. 5. The (i) in the sense organs detect stimuli. 6. Humans have (j)______sense organs for detecting the environment.

(E) Short questions (20 marks) 1. The following table shows the operating currents of three electric appliances. electric kettle electric iron air conditioner Operating current 5A 4.5A 10A

If these appliances are connected to the same 15A fused socket and they are switched on together, what will happen to the fuse? Why? (4 marks)

2. Find out the position of the sliding contact of the rheostat at which the bulb will be the brightest. Give a reason for your answer. (3 marks)

3. All the light bulbs in the following circuit are identical.

0.2 A B

(a) Which bulb is the brightest when the circuit is closed? (1 mark) (b) Draw in the diagram to show how to measure the voltage of bulb B. (1 mark) (c) Calculate the total amount of current being drawn from the battery. (1 mark) (d) If bulb B burns out, what happens to bulb A? (1 mark)

4. 10 pieces of apple are kept in (A) a beaker of water and (B) a beaker of vinegar respectively for a week. The results are recorded as follows. Beaker Results A Apple pieces turn bad B Apple pieces are still fresh

(a) Which liquid can preserve apple? Why? (2 marks) (b) What is the conclusion of this experiment? (2 marks) (c) State 2 advantages of preserving food with acid. (2 marks) (d) Suggest 3 other methods of preserving food. (3 marks)

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