CBSE Class 8 Science Sample Paper Half Yearly Examination

CBSE Class 8 Science Sample Paper Half Yearly Examination


Sub- Science

Time: 3 hour


1- Choose the correct option:(5)

i) Each repeating unit in a polymer is called…….

a) Dimmer

b) Monomer

c) Trimmer

ii) Metals react with acid to produce…..

a) Chlorine

b) Hydrogen

c) Oxygen

iii) Coal mainly contain –

a) Carbon

b) Sodium

c) Hydrogen

iv) Which of these is a source of energy?

a) Coal

b) Plastic

c) Animal

v) Which of these is a primary fuel?

a) Wood

b) Biogas

c) Paraffin wax

vi) Excess of which gas leads to global warming?

a) Carbon dioxide

b) Ozone

c) Oxygen

vii) Which of the following is not a natural eco system?

a) Aquarium

b) Forest

c) Pond

viii) The storage compartment of the cell are –

a) Cytoplasm

b) Vacuole

c) Nucleus

ix) Binary fission is seen in –

a) Hydra

b) Amoeba

c) Centrioles

x) The suicidal bags of the cell are –

a) Nucleoli

b) Ribosomes

c) Lysosomes

2- State True or False according the statement.(5)

i) Large-sized vacuoles are present in animal cells.

ii) Chromoplasts are found in the green parts of the plant.

iii) Centrosome is found only in animal cells.

iv) Flora means plants and fauna means animal.

v) Ecosystem is the clearing of forests for agriculture.

vi) Biosphere is part of earth that support life.

vii) We can use water in case of electrical fire.

viii) Coal is also called black gold.

ix) Sodium is the hardest non- metal.

x) We can use alcohol in the thermometer.

3- Fill in the blanks –(5)

i) ______ is called a cellulosic polymer.

ii) Zinc is more ______ than copper.

iii) The liquid fossil fuel is______

iv) The compounds made from petroleum is called ______

v) The substance which _______ easily on burning give flames.

vi) __________reaction is accompanied by the evolution of heat.

vii) The animals near extinction are called __________

viii) ______ are the male gonads of human bengs.

ix) Frogs undergo______ to become adults from tadpole.

x) The full form of AIDS ______.

4- Write answer in one word or two.(5)

i) This is a thermo set that extreme heat ______.

ii) A metal which explodes in water __________.

iii) The property that allows material to be drain into wires ______.

iv) The name of a coal that has highest carbon______.

5- Match the hormones with the endocrine glands –(6)

A                                 B

i) Thyroxin                   Adrenol

ii) Insulin                     Thyroid

iii) Growth hormone    Ovary

iv) Adrenaline             Testes

v) Oestrogen              Pituitary

vi) Testosterone         Pancreas

6- Differentiate between –(8)

i) Sanctuary and zoo

ii) Ecosystem and biosphere

iii) Complete and uncompleted combustion

iv) Thermoplastic and Thermo sets

7- Write short answer – (do any eight)(16)

i) What are autosomes?

ii) What are gonads and what do they produce?

iii) What is meant by the term reproductive phase in females?

iv) What is cloning?

v) What is fertilization?

vi) Describe the function of the cell wall.

vii) What is migration? Why do animals migrate?

viii) How does carbon dioxide help in extinguishing fire?

ix) What is the impact of using excess of fossil fuel?

x) What are displacement reactions? Give examples.

8- Long answer type questions [ Do any four ](16)

i) Which viruses Aids? What are the ways in which it can be transited?

ii) What is reproduction and what is its significance?

iii) What does the cell theory state?

iv) What is migration? Why do animals migrate?

v) What are the harmful effects of burning fuel?

vi) How are polybags harmful to animal and small children?

9- Correct the following statement by replacing the incorrect word – (4)

i) Polyester is used as an alternative to wool.

ii) Thread-like structures in the nucleus are called chloroplasts.

iii) Puberty starts with menopause in women.

iv) Men have smaller voice boxes than women.

10- Draw any two labeled diagram neatly – (10)

i) The human female reproductive system

ii) Life cycle of a frog

iii) An animal cell

iv) A microscope

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