CBSE Class 9 Science Exam 2020: Important Very Short Answer Type Questions with Answers
Just reading the chapters and mugging the concepts and theories is not enough to get prepared for the exams. Solving problems based on those concepts is necessary to understand their application. So, we are providing here a set of important questions to prepare for Class 9 Science Annual Exam 2020. These are the questions which must be practiced to attempt the 1 marks questions in exam with ease and precision.
Question number 1-14 in Section-A of Science paper will be all one mark questions. These questions will be asked in different formats like very short answer type questions, multiple choice type questions, etc. Practicing with the important questions provided below, will certainly help you answer different questions appropriately by strengthening your fundamental concepts.
Given below are some very important questions for ‘very short answer type questions’ category in class 9 Science exam 2018:
1. What is rancidity?
The process in which taste and smell of food gets spoiled is called rancidity. It happens due to oxidation.
2. Name the particles which determine the mass of an atom.
Proton and neutron.
3. Who discovered neutron?
4. Mention two uses of isotopes in the field of medicine.
(i) An isotope of cobalt is used in the treatment of cancer.
(ii) An isotope of iodine is used in the treatment of goitre.
5. Name the characteristics of sound wave on which the following properties depend?
(a) Loudness depends on amplitude
(b) Pitch depends on frequency.
6. Write any two charateristics of the animals belonging to phylum chrodata.
Two charateristics of the animals belonging to phylum chrodata are:
(i) They are bilaterally symmetrical, triploblastic and have body cavity.
(ii) They exhibit notochord, a flexible rod between the nerve cord and the digestive track, at some stages during development.
7. Who discovered vaccine for the first time?
Edward Jenner discovered vaccine for the first time.
8. Alloy cannot be separated by physical means, though it is considered a mixture. Why?
Alloys are homogeneous mixtures of metals and cannot be separated into their components by physical methods. But still, an alloy is considered as a mixture because it shows the properties of its constituents and can have variable composition.
9. Find the relative density of copper block of mass 216g having volume of 80cm3 (Density of Water = 1g/ cm3).
Density of block = Mass/volume = 216/80 = 2.7 g/cm3
Relative density = Density of a substance / Density of water = 2.7/1 = 2.7
10. What do you mean by the planetary electrons?
Rutherford compared his model of an atom with our solar system where the nucleus is like the sun and the electrons are like the planets. Thus, these electrons are also called planetary electrons.
11. What is a thallus? Why are thallophytes called non-embryonic plants?
Thallophyte has a simple plant body structure with no distinct root system, stem and leaves. Such simple body is called thallus.
Thallophytes have unicellular gametes. After fertilisation, the zygote does not form an embryo. Therefore, these plants are called non-embryonic plants.
12. Why did Rutherford select a gold foil for his experiment?
Rutherford selected a gold foil for his experiment as he wanted a very thin layer and gold is highly malleable.
13. Why do fish go in deep waters during day light?
During day time, the shallow water is warmer and hence contains less dissolved oxygen. Therefore fish tend to go in deep water during day time.
14. Name two properties of a substance to check its purity?
A pure substance has a fixed melting point or boiling point at constant pressure. The purity of a substance can be tested by checking its melting point or boiling point. If a substance is impure i.e. it contains traces of another substance, the melting and boiling point of that substance will change.
15. What is meant by warm-blooded and cold-blooded animals?
Warm-blooded animals have a relatively higher blood temperature and can maintain the constant internal body temperature through metabolic processes. Mammals and birds are warm-blooded animals.
16. State the utility of tissues in multi-cellular organism.
We see division of labour in multi-cellular organism as a particular function is carried out by a cluster of cells (tissue) at a definite place in the body. The tissues are arranged and designed in such a way that they give the highest possible efficiency of function.
17. What do you mean by intensive and extensive properties of matter?
Extensive properties, such as mass and volume, depend on the amount of matter being measured.
Intensive properties, such as density and color, do not depend on the amount of the substance present.
18. 100 g of 10% lead nitrate is mixed with 100 g of 10% sodium chloride solution in a closed container. 13.66 g of lead chloride is precipitated. The mixture contains 180 g of water and sodium nitrate. What amount of sodium nitrate is formed?
Mass of lead nitrate = 10% of 100 g = 10 g
Mass of sodium chloride = 10% of 100 g = 10 g
Mass of water = 90 g + 90 g = 180 g
Total mass = 10 g + 10 g + 180 g = 200 g
Mass of water = 180 g
Mass of lead chloride = 13.66 g
Now by law of conservation of mass,
Total mass of reactants = Total mass of products = 200g
Thus, mass of sodium nitrate = 200 g – (180 g + 13.66 g) = 6.34 g
19. State the types of meristems present in plants, on the basis of position.
On the basis of location of meristems, it classified as follows:
(i) Apical meristem,
(ii) Intercalary meristem,
(iii) Lateral meristem.
20. What are intermolecular forces? How are these related to the three states of matter?
Intermolecular force: It is the force operating between the atoms or molecules of a matter.
In case of solids this force keeps the constituent particles very close to each other and gives them an ordered arrangement of resulting into a regular geometrical shape in solids.
In liquid, intermolecular force is weak to give definite shape.
In gas, intermolecular force is negligible and so its constituent particles are free to move and occupy the available space.
21. (a) On the basis of Thomson’s model of an atom, explain how the atom is neutral as a whole?
(b) Where are electrons found in the atom?
(a) According to Thomson’s model of the atom, an atom consists of both negatively and positively charged particles. The negatively charged particles are embedded in the positively charged sphere. These negative and positive charges are equal in magnitude. Thus, by counterbalancing each other’s effect, they make an atom neutral.
(b) Electrons are found in shells or orbitals that surround the nucleus of an atom.
22. (a) Which postulate of Dalton’s atomic theory is the result of law of conservation of mass?
(b) Name the term which is used for the symbolic representation of a molecule of an element or a compound? Give an example of it.
(a) The postulate that “atoms can neither be created nor destroyed in a chemical reaction” is the result of the law of conservation of mass.
(b) The symbolic representation of a molecule of an element or a compound is known as chemical formula. For example, molecular formula of water is H2O.
23.(a) Write two points of difference between amphibians and reptiles.
(b) Mention two characteristics which help amphibians to survive on land.
(a) Difference between amphibians and reptiles is stated below:
These are aquatic or terrestrial.
These have terrestrial habitat.
They breathe through lungs or gills.
The breathe only through lungs.
They have smooth, slimy, non-scaly exoskeleton.
Their body is covered by waterproof scaly exoskeleton.
Examples – Frog
Examples – lizard, snakes crocodiles, etc.
(b) Two characteristics which help amphibians to survive on land are:
- Presence of lungs which facilitate breathing on land
- Presence of protective skin that prevents loss of water from within the body
24. (a) Name any two abiotic factors that make soil.
(b) What would happen if all the oxygen of the environment is converted to ozone?
(a) Abiotic factors making soil are sun, water, wind.
(b) Ozone is a poisonous gas which is present in the stratosphere in the form of a thin layer in. lf all the oxygen is converted to ozone, the environment will become poisonous and kill all living forms.
25. What are the two ways to treat an infectious disease?
Name any two sexually transmitted diseases.
(a) (i) Kill the cause of disease.
(ii) Reduce the effects of the disease.
(c) Two sexually transmitted diseases are:
(i) Acquired Immune Deficiency Syndrome (AIDS)
26. (a) State any two conditions essential for good health.
(b) How are antibiotics effective in treatment of some diseases?
(a) Two conditions that are essential for good health are:
(i) Proper nutrition and a blanced diet
(ii) Good Social environment.
(b) It blocks the bacterial synthesis pathway without affecting our own. It blocks the bacterial processes that build the cell wall. As a result, the disease causing bacteria become unable to make cell-walls, and die easily.
27. How is loudness of volume distinguished from its intensity?
Sound intensity is the amount of energy carried by sound whereas loudness is a measurement of the audible sound.
28. What is the mass of
(i) 0.2 mole of oxygen atoms?
(ii) 0.5 mole of water molecules?
(a) Mass of 1 mole of oxygen atom = 16 u
Mass of 0.2 mole of oxygen atoms = (16 × 0.2) u = 3.2 u
(b) Mass of 1 mole of H2O molecule = (1 × 2 + 16) = 18 u
Mass of 0.5 mole of H2O molecule = (18 × 0.5) u =9 u.
29. In which two categories, the organisms are divided on the basis of evolution? How are the two categories different from each other?
On the basis of evolution, the organisms are divided into two categories :
(a) ‘Primitive’ or ‘lower’ organisms
(b) ‘Advanced’ or ‘higher’ organisms
Advanced organisms are the result of gradual development of more complex organisms from the simpler ones i.e., primitive organisms.
30. Write the features which formed the basis for grouping the organisms into five kingdoms.
Answer. The basis for grouping organisms into five kingdoms depends on their:
(a) Cell structure.
(b) Mode and source of nutrition.
(c) Body organisation