CBSE Sample Paper 2021 Class 8 Science Half Yearly

Half Yearly Examination (2020-21)


Time:2:30 hours

Maximum Marks:80

Subject: Science

All questions are compulsory.

1- Choose the correct options:- (6)

i) Coal mainly contains :-

a- Carbon

b- Sodium

c- Hydrogen

ii) Which of these is not a source of energy?

a- Plastic

b-  sun

c- Coal

iii) Which of these does not help in starting fire?

a- Heat

b- fuel

c- Water

iv) Which of the following is not a natural?

a- Grassland

b- aquarium

c-  Chloroplasts

v) Male gonads are called –

a- Testes

b- ovaries

c- penis

2- Match the following :-(6)

A                                              B

i) Cell wall                      Hydra

ii) Nucleus                      female gametes

iii) Ribosome                  controls all the activities of the cell.

iv) Egg                             Amoeba

v) Budding                      Protein synthesis

vi) Binary fission             Protection and shape

3- Fill in the blanks :- (8)

i- The liquid fossil fuel is ____________.

ii- ____________ should never be used in case of an electrical fire.

iii- The animals nearing extinction are called ____________.

iv- Internal fertilization takes place in____________.

v- ____________ are the female gonads of human beings.

vi- ____________ involves the splitting of an organism into two.

vii- ____________ release sperm.

viii- In humans fertilization occur in____________.

4- Write T for the true statement and F for the false statements: -(8)

i- Large – sized vacuoles are present animal’s cells.

ii- The cell membrane is selectively permeable.

iii- Flora means plants and fauna means animals.

iv- Ecosystem is the clearing of forests for agriculture.

v- Centrioles help in cell division in animal cells.

vi- Chromo plasts are found in the green parts of the plants.

vii- Amoeba is a single – Celled animals.

viii- Reforestation could lead to and increases in carbon- dioxide.

5- Give reasons for the following.(8)

i- LPG is a better fuel than wood.

ii- Water should not be used in case of a fire in a petrol tank or an electric fire.

iii- A washer man uses charcoal for ironing clothes.

iv- CNG is a better fuel for automobiles.

6- Answer the following questions in one word :-(8)

i- Name a cooking gas.

ii- What is called a black gold?

iii- The gradual conversion of fertile soil into wasteland.

iv- What is called if trees are cutting on a large scale?

v- Name a type of coal which has the highest carbon content.

vi- The process of extraction of resources from earth.

vii- Name the compounds made from petroleum.

viii- Name a moth repellent made from coal tar.

7- Short answers type questions. (Do any eight) (16)

i- What is the impact of using excess of fossil fuels?

ii- What are the characteristics of an ideal fuel?

iii- Why are biodiversity parks being made in different ports of India?

iv- Why the nuclease is called the control centre of the cell.

v- List the male and female reproductive organs of human body?

vi- What are the functions of vacuoles?

vii- Why are biodiversity parks being made in different park s of India?

viii- Why substances do produces flames of different colors?

ix- Why is conservation of fossil fuels essential?

x- What are gonads and what do they produce?

8- Long answers type questions (Do any four) (16)

i- Which virus causes AIDS? What are the ways in which it can be transmitted?

ii- Explain menstrual cycle and the changes that occur in an adolescent girl during the menstrual cycle?

iii- Life begins from a single cell called zygote Explain the statement.

iv- How does fertilization take place in frogs?

v- What are the cell theory states?

vi- How can citizens help in the conservation of plants and animals?

9- Draw any one lablled diagram of the following :- (4)

i- Life cycle of a frog

ii- A plant cell

iii- A candle flame