Summative Assessment – II (2010-2011)

Subject: Science(Set 1)Marks : 100

Grade : VIII Time: 2½ hrs

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Note: 1. Physics, Chemistry and Biology to be done on separate answer sheets.

  1. Draw neat labeled diagrams wherever asked.

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(PHYSICS-33 marks)

I. Choose the correct choice.(1x10 = 10)

  1. Various sounds were recorded using a microphone and the signal displayed on an oscilloscope (CRO). Which sound wave can produce louder sound?
  1. sound4 b.sound1c.sound3 d.sound 2
  1. What would be a good material on the floor to muffle the sound of footsteps?

a. carpetb. metal c. wood d. marble

  1. Frequency of ultrasonic sound wave is

a. Greater than 20 Hz b. Greater than 20,000 Hz

c. Greater than 2 Hzd. Greater than 2 MHz

  1. 5 oscillations for a pendulum in one second is
  1. 0.5 Hz b. 5 Hzc. 50 Hzd. 0.05 Hz
  1. Characteristic of sound that enable us to distinguish between two sounds of same pitch and same loudness is known as
  1. amplitude
  2. frequency
  3. quality
  4. intensity
  1. Which is NOT true about sound?
  1. light travels much faster than sound
  2. soft materials are good sound absorbers
  3. If the amplitude is increased by three times then the loudness also increases by three times.
  4. eardrums can be gradually and permanently damaged by continuous moderately loud sounds
  1. A car is heading towards south . The force of friction acting on the car is towards

a. south b. west.

c. north d. east.

  1. There are three surfaces, one being glass, second wood and third sand. The increasing

order of friction of the surface is

a. sand, glass and woodb. wood, glass and sand.

c. glass, sand and woodd. glass, wood and sand

9. The Pole star is in the constellation of

a. Ursa Majorb. Ursa Minor

c. Orion d. Scorpius

10. The large number of rocks lie between the orbits of Mars and Jupiter are called

a. cometsb . satellites

c. asteroidsd. meteorites

II. Answer the following. (1x4 = 4)

  1. What is the name of the strings in the human voice box which vibrate to produce

sound?

2 Name the unit of measuring loudness?

3. On what principle do ball bearings work?

4. What makes venus the hottest planet though it is not closest to the sun?

III. Answer in brief (2x4 = 8)

  1. Which of the above two graphs A and B representing the human voice is likely to be a male voice? Give reason for your answer.
  1. a. Why is it difficult to talk in an empty room?

b. The difficulty is removed if the room has furniture and curtains. Why?

  1. How does a lubricant reduce friction? Name one solid lubricant and state where it is used?
  1. Write one point difference between an artificial and natural satellite. Give two ways in which artificial satellites are useful for us?

IV. Answer the following. (3x2 = 6)

  1. A) Will the sound of a train travel faster through the air or through railway tracks? Why?

b) Why is the lightning seen at once, but the clap of the thunder is heard after some time? What is the speed of sound in air?

2. Explain the following

a)Why does friction occur between two surfaces in contact?

b)Why is the boat or an aero plane given a special shape? What is the shape given?

V. Answer the following.

The diagram given below is that of a simple pendulum. Attempt the questions that follow based on it: [5 marks]

  1. Name the positions marked A, B and C.
  2. What does BC measure?

c. Define time period of the oscillating body.

d.How can the time period of the pendulum be changed?

e.If the pendulum makes 10 oscillations per second, what will be its frequency?

CHEMISTRY(33 Marks)

Q I Choose the most appropriate answer (1x10=10)

1. Name the ore from which iron is extracted.

a)Haematitec) Bauxite

b)Copper glanced) Zinc blende

2. Which of the following can be beaten into thin sheets?

a) Zincc) Phosphorus

b) Sulphurd) Oxygen

3. In the free state carbon occurs as

a) Carbon monoxidec) Diamond

b) Carbon dioxided) All of these

4. When metals react with water which gas is given out?

a) Oxygenc) Hydrogen

b) Carbon dioxided) None of the above

5. Which metal is electroplated on iron to give it corrosion resistant shining finish?

a) Chromiumc) Tin

d) Aluminiumd) Zinc

6. If the purity of gold is 18 carat. What is the percentage of gold in ornament?

a) 50%c) 100%

b) 25%d) 75%

7. Which of the following is used in making match boxes and in fireworks industries?

a) Carbonc) Phosphorus

b) Silicond) Sulphur

8. Which of the following is also known as artificial silk?

a) Nylonc) Polyster

b) Rayond) Acrylic

9. Which of the following is not made of thermoplastics?

a) Electrical switchesc) Thermocol

b) Plastics chairsd) Toys

10. Which of the following is the natural polymer?

a) Poly cotc) Rayon

b) Cellulosed) Acrylic

Q II.Give one word answer( 1x4=4)

  1. Name the plastic used for making non-stick pans?
  2. Melamine is made of which type of plastic?
  3. Name the metal that occur in free state?
  4. Which alloy will be most useful to you if you are an engineer constructing a multistory building?

Q III Give reasons (2x4=8)

1. Why are electric wires are covered with plastics?

2. Why nylon is used in making ropes for rock climbing?

3. An iron knife kept dipped in blue copper sulphate solution changes to light green. Why?

4. Phosphorus is stored under water

Q IV Answer the following questions.(3x2=6)

1. A set of metals in order of their increasing reactivity is given below: Silver, copper, lead, iron, zinc, magnesium, potassium and sodium

a) Which of the above metal is stored under kerosene?(1/2 mark each)

b) Which metal react with cold water?

c) Which of the metal will react with oxygen when heated?

d) Which of the metal become black in presence of hydrogen sulphide?

e) Which metal is used for making electrodes?

f) Which metal react with only steam?

2. Define polymer. Write four advantages synthetic fibres have over natural fibres?

V Study the diagram shown below carefully and answer the following questions. (5)

A.1. Which process is taking place in below diagram?(1/2M)

2. Write the use of that process?(1 M)

3. What is the advantage of galvanized iron over tin-plated iron? (2M)

B. 1. Which gas is evolved after the reaction?(1/2 M)

2. How will you test the nature of gas evolved? (write reaction) (1 M)

Biology (34 Marks)

Q1: Choose the most appropriate option. 1x10=10

1-Project Tiger was started in India in year-

A-1971

B-1973

C-1981

D-1975

2-Which of the following is odd one out with respect to fertilization

A-Snake

B-Jelly fish

C-Frog

D-Fish

3-Fusion of a male and gamete is called

A-Cell maturation

B-Cell division

C-Menstruation

D-Fertilization

4-In humans, there are ...... chromosomes.

A-46

B-44

C-48

D-42

5-Amoeba reproduces by

A-Multiple fission

B-Spores

C-Binary fission

D-Budding

6- In humans, the development of zygote reaches the stage of foetus in-

A-8 weeks

B-6 weeks

C-9 months

D-9 weeks

7-The species which are found in limited geographical regions are called

A-Endemic species

B-Endangered species

C-Vulnerable species

D-Critically endangered species

8-The fertilization in humans takes place in

A-Uterus

B-Ovary

C-Oviduct

D-Vagina

9-The hormone produced by ovaries in humans is

A-Oestrogen

B-Insulin

C-Thyroxin

D-Progesterone

10-Which of these is not a result of deforestation

A-Global warning

B-Desertification

C-Storms

D-Result in ground water level

QII: Give Very Short Answers. 1x5=5 Marks

1-What are the two methods to control forest fires?

2-Name two species of animals to have become extinct in recent past.

3-Name two animals which reproduce by binary fission.

4-What are viviparous animals?

5-What is target site?

QIII: Give Short Answers. 2x4= 8 Marks

1-What are ductless glands? These are included in which system of the body? What are the chemicals called secreted by ductless glands?

2-What is the difference between sexual and asexual reproduction?

3-What is an ecosystem?

4-Why are more than one babies born to cats and dogs at one time?

QIV: Long Answers. 3x2= 6 Marks

1-A- What is the difference between planned harvesting and afforestation? 2 Marks

B- What is the difference between flora and fauna?1 Mark

2-Explain how the gender of the human babies is determined? 3 Marks

QV: Very long answers. 5 Marks

1-Label in the diagram marked A and B 1 mark

2-Name the process being shown in the diagram and define it.2 marks

3-Name the hormone required for this process in frogs1 mark

4-Explain how this type of development is different from normal development?1 mark

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