LEADERS PRIVATE SCHOOL, SHARJAH HOLIDAY ASSIGNMENT-SCIENCE GRADE: VIII

Transcription

1 LEADERS PRIVATE SCHOOL, SHARJAH Name: HOLIDAY ASSIGNMENT-SCIENCE GRADE: VIII Date: LEVEL-1 1. Figure shows two plane mirrors inclined to each other i) What is this set up called ii) On what principle does it work? iii) Where is it used? (iv) On the Fig, clearly mark the angle of incidence i and the angle of reflection r at Mirror A (v) State the equation linking i and r. (vi) The light ray strikes on the mirror A at 45 ο to the normal, find the angle of reflection at mirror B 2. Is it the plane mirror which causes lateral inversion of the image? Explain your answer. 3. The distance between the object and the image is 48cm. Determine the object. Distance and the Image distance. 4. Define the terms lateral displacement and angle of deviation. 5. Which optical phenomena causes the rainbow? Why? 6. Boojho and Paheli performed experiments taking similar bulbs and cells but two different solutions A and B as shown in Fig.

2 They found that the bulb in the setup A glows more brightly as compared to that of the setup B. You would conclude that (a) Higher current is flowing through the circuit in setup A. (b) Higher current is flowing through the circuit in setup B. (c) Equal current is flowing through both the circuits. (d) The current flowing through the circuits in the two setups cannot be compared in this manner. 7. Which of the following solutions will not make the bulb in the figure glow? (a) Sodium chloride (b) copper sulphate (c) silver nitrate (d) sugar solution in diluted water 8. Complete the crossword figure with the help of the clues:

3 Across Down 1. Non-metal which catches 2. A chemical process in fire if exposed to air which a substance reacts With Oxygen to give off Heat. 3. The lowest temperature at 4. Petrol is used as a Which a substance catches in Fire is called its automobiles. Temperature. 5. The most common fire 6. It is as hard as stone & extinguisher. black in colour. 9. If you hold a piece of iron wire with a pair of tongs inside a candle flame or a Bunsen burner flame, what will you observe? Will it produce a flame? 10. Why is the use of diesel and petrol as fuels in automobiles being replaced by Compressed Natural Gas (CNG) in big cities? 11. Identify the unicellular organisms that has no definite shape. a) Amoeba b) paramecium c) Euglena d) Bacteria 12. The cytoplasm & the nucleus together makeup the. 13. The fusion product of sperm & ovum is known as. a) Egg b) Zygote c) pupa d) Ovary

4 14. The transformation of the larvae into an adult through drastic changes is called. 15. In the offspring s grows out of the parent s body. a) Hydra b) Amoeba c) Paramecium d) Human LEVEL Under what condition the angle of incidence is equal to the angle of refraction? 2. Why does the stick partly immersed in water appears to be bent? Explain with the help of a diagram. 3. Kajal who has just begun to learn swimming is in the pool. Suddenly she finds her gold earring falling into the water. She feels that the earing has not gone too deep and she goes into the water to retrieve it. Her trainer observing this pulls her out.explain why did he do so? 4. Can a glass slab bend different coloured lights by different amounts? Give reason.

5 5. Explain the phenomena shown in the figure 6. Smitha made the circuit given in the figure and observed that the bulb did not glow. On Meera s suggestions she added one more cell in the circuit. The bulb now glows. Explain. 7. Give reasons for the following i) After a road accident, petrol and oil that have spilled on the road are covered with sand. ii) The flame of a kerosene lamp is yellow whereas the colour is blue in a wick stove. iii) Paper by itself catches fire easily whereas a piece of paper wrapped around an Aluminium pipe does not. 8. Pencils that are sharpened from both sides can be used as electrodes. Why? 9. In case of a fire, before the firemen use the water hose, they shut off the main electrical supply for the area. Explain why they do this.

6 10. When paper burns, a lot of black soot rises up, what does it tell about the nature of paper? 11. Classify the following terms into cells, tissues and organs. RBC, WBC, Nerve cell, Blood, muscle, Blood vessels. Brain, heart, Hand. 12. Read the following statement and write the appropriate terms. a) I control the functions of a cell. Who am I? b) I am like a policeman. I do not allow anything and everything to get in and out of the cell. Who am I? c) I transfer character from parents to offspring s. Who am I? 13. What advantages does amoeba derive by changing its shape? Which part of the cell gives its shape? 14. The number of chromosomes are definite in each species. Every human body cell has 46(23 pairs). Find the chromosome number in : Onion, Lion, Monkey, Sugarcane. 15. Mother gives birth to a baby but the baby has characters of both the parents. How is this possible? LEVEL A ray of light passes through one surface of a glass prism at right angles to the surface,

7 State why the ray is not deviated as it passes through the surface into the glass at A. 2. Trace the path of light through a glass slab and prism 3. Distinguish between the lateral displacement and angle of deviation 4. Describe the formation of rainbow with the help of a ray diagram. 5. In the figure shown, a magnifying glass is used to burn the paper. a. Which lens is used as a magnifying glass? b. At what position of the lens is the image of the sun formed c. The paper starts burning. Give reason d. The Image of the sun on the lens is very small, then why is this lens called magnifying glass. e. What type of image is formed in the experiment shown? Why? f. Give two examples of the usage of this lens in our real life 6. You are provided with a magnetic compass, an empty match box, a battery of two cells and connecting wires. Using these objects how will you make a tester for testing an electric circuit? Draw the necessary circuit diagram and explain. 7. Rahul made the circuit shown in figure. He wanted to observe what happens when an electric current is passed through water. But he forgot to add a few drops of lemon juice to water. Will it make any difference to his observations? Explain.

8 8. Ravi was playing with the flame of candle and perchance he got hurt and burnt his finger, but his friend Shivam placed his finger again in the flame and was not hurt. i) Why was Shivam not hurt? ii) Which kind of value did Ravi possess? 9. Payal had heard that rainwater is as good as distilled water. So she collected some rainwater in a clean glass tumbler and tested it using a tester. To her surprise she found that the compass needle showed deflection. What could be the reasons? 10. Manu was heating oil to fry potato chips. The cooking oil all of a sudden caught fire; he poured water to extinguish the fire. Do you think this action was suitable? If yes, why? If not, why not? 11. Find out about Bt cotton with help of internet. Prepare a short note on its advantages and disadvantages. 12. Debate on the topic with your views. Is cloning an ethical or unethical practice.? 13. Prepare a short speech for your class on genetically modified (GM) crops.

9 14. Find out the difference between identical and non- identical twins. Also find out why identical twins are always of same sex. 15. Collect information about various types of microscopes and prepare a project on it. High light the functions, applications and importance in day today life. ******************************************************************

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