Practice Paper – TERM II (2021 – 2022)
Class – IX
Science (086)
Time: 2 hours Maximum Marks: 40
General Instructions:
i) All questions are compulsory.
ii) The question paper has three sections and 15 questions. All questions are compulsory.
iii) Section–A has 7 questions of 2 marks each;
iv) Section–B has 6 questions of 3 marks each; and
v) Section–C has 2 case based questions of 4 marks each.
vi) Internal choices have been provided in some questions. A student has to attempt only one of the alternatives in such questions.
SECTION – A
1. Under which of the following conditions are you most likely to fall sick?
(a) When you are taking examinations
(b) When you have travelled by bus for two days.
(c) When your friend is suffering from measles. Why?
C, Measles is a communicable disease.
2. Write the full form of AIDS. Name the virus responsible for its cause.
Acquired Immune Deficiency Syndrome, Human Immunodeficiency virus.
3. If number of electrons in an atom is 8 and number of protons is also 8, then
(i) What is the atomic number of the atom?
8
(ii) What is the charge on the atom?
O2-, Anion
4. What is the magnitude of the gravitational force between the earth and a 1 kg object on its surface? (Mass of the earth is 6 x 1024 kg & radius of the earth is 6.4 x 106 m)
By using F = G Mm /r2 = 9.81 N
OR
Derive the expression for universal law of gravitation.
Required expression
5. (i) When do we say that work is done?
When force is applied and displacement takes place
(ii) Give an example of zero work done.
A porter carrying luggage over his head or any other suitable answer
6. State giving reasons whether the following statements are correct or incorrect.
(i) Health is only the absence of any physical disease.
This statement is incorrect because health is a state of complete physical, mental and social well-being not merely the absence of disease.
(ii) Children need not be immunized.
This statement is incorrect because children need to be immunized because of poorly developed immune system.
OR
Why antibiotics are ineffective against viruses?
It is because viruses have different mechanism and machinery to survive and replicate.
7. Classify the following diseases as infectious or non-infectious:
(a) Tuberculosis – Infectious
(b) Malaria – Infectious
(c) High blood pressure – Non-infectious
(d) Chickenpox – Infectious
SECTION B
8. Write any three postulates of Dalton’s atomic theory.
i. All matter is made of very tiny particles called atom
ii. Atoms are indivisible and indestructible.
iii. Atoms of the given element are identical in mass and chemical properties or any other postulates.
OR
(i) What do you mean by electronic configuration of an atom?
The distribution of electrons in various shells of an atom
(ii) Write the electronic configuration for Magnesium and Chlorine atom.
Mg = 2, 8, 2 & Cl = 2, 8, 7
9. (a) What is kinetic energy of a body?
The energy possessed by a body by the virtue of its motion.
(b) Derive the expression for kinetic energy.
W = F x S
Or F = m x a
By using, v2 – u2 = 2aS or v2 – u2/2a = S
10. (a) Write one point of difference between isotopes and isobars.
Isotopes are the atoms of the same element, having same atomic numbers but different atomic masses while isobars are the atoms of the different elements with same atomic masses but different atomic numbers.
(b) Write any two applications/uses of isotopes.
Any two uses
11. In a gold foil experiment –
(a) Why did many alpha particles pass through the gold foil undeflected?
It is because most of the space inside the atom is empty
(b) Why did few alpha particles deflect through small angles?
There is positive charge at the Centre of the gold foil that occupies very little space.
(c) Why did few alpha particles, after striking the gold foil, retrace their path
Nucleus of the atom is very small as compared to the total size
OR
Write any three postulates of Bohr theory.
i. Electrons move around the nucleus in definite circular paths called orbits/shells
ii. Each orbit is associated with fixed amount of energy
iii. Electrons can move from one orbit to another by gaining/losing a fixed amount of energy.
12. (a) Define 1 joule of work.
When a force of 1 N is applied to displace a body by a 1 m
(b) Certain force acting on a 25 kg mass changes its velocity from 6 m/s to 4 m/s. Calculate the work done by the body.
250 J
13. Why metals are electropositive whereas non-metals are electronegative in nature?
Metals have the tendency to lose electrons to acquire positive charge whereas non-metals gain electrons to acquire negative charge.
SECTION C
This section has 2 case study based questions (14 & 15). Each case is followed by three sub-questions (a, b & c). Part a & b are compulsory. However, an internal choice is provided in section c.
14. Read the following passage and answer the questions given below:
According to Universal law of gravitation, the force of gravitation between two particles/bodies is directly proportional to product of their masses and is inversely proportional to the square of the distance between them. G is a universal constant as it value remains the same throughout the universe whereas g is gravity and it is the force with which anybody gets attracted towards the surface of the earth and its value changes from place to place.
(a) What is the SI unit of G?
Nm2/kg2
(b) How does the force of gravitation between two objects change when the distance between them is reduced to half?
Force becomes four times
(c) Calculate the force of gravitation between the earth and the sun, given that mass of the earth is 6 x 1024 kg and of the sun is 2 x 1030 kg. The average distance between the two is 1.5 x 1011 m.
3.6 x 1020 N
OR
State any two importance of universal law of gravitation.
i. This law explains well the force that binds us to the earth
ii. This law describes the motion of the planets around the sun or any other point of importance.
15. An atom is the smallest particle of matter. There are three sub-atomic particles of an atom i.e., electrons, protons and neutrons. The number of electrons gives the idea of the atomic number of an atom. The tendency to gain or lose electrons decides the charge of an atom.
(a) What is the charge present on Sulphur atom?
Anion, negative
(b) What would be the valency, if the atom has 3 protons and 4 neutrons in its nucleus?
Valency = 1
(c) i. What is atomicity?
The number of atoms present in one molecule of a substance
ii. How many atoms are present in PO43- ion and NO3 ion?
5 atoms & 4 atoms
OR
What makes an atom electrically neutral?
When the magnitude of negatively charged particles is equal to magnitude of positively charged particles