Class 9 Sample Paper Science 2019

SECTION – A

Question 1:
What do you mean by the word “mole” ?
Answer:
The mole is the amount of substance that contains the same number of particles (atoms/ions/ molecules/formula units, etc.), as there are atoms in exactly 12 g of carbon-12.
Question 2:
What is the ratio of forces between two masses kept at a certain distance in air to the force between them when kept in any other medium ?
Answer:
1 : 1, because the gravitational force is independent of the nature of the medium in which the bodies are placed.
Question 3:
How do bats move about freely even in dark nights and search out prey ? Name the sound waves used by them and write their frequency.
Answer:
Ultrasonic waves emitted by bat are reflected from prey and received by their ears. So they locate obstacles..
Sound wave – Ultrasound, Frequency – Above 20000 Hz.
Question 4:
What is epidermis? List three functions of epidermis.
Answer:
Epidermis is a single layer of cells that covers all the parts of the plant externally
Functions:
(i) Protection: It protects against loss of water, mechanical injury and invasion by parasitic fungi.
(ii) Secretion: Epidermal cells on the aerial parts of the plant often secrete a waxy layer which further helps in protection from mechanical injury and water loss.
(iii) Absorption: Root hairs present on epidermis of root help ip absorption of water and minerals from the soil.
Question 5:
Write the chemical formulae for the following compounds and find the ratio by mass of the combining elements in each one of them. (N = 14 u, H = 1 u, C = 12 u, O = 16 u, S = 32 u)
(a) Methane
(b) Carbon dioxide
(c) Hydrogen sulphide
Answer:

Question 6:
(a) Do isobars belong to the same element ? Justify your answer by giving one example.
(b) Name two elements whose isotopes are used in the field of medicine.
OR
(a) Mention the steps taken by you or your family members when you fall sick ?
(b) List two ways to treat an infectious disease.
Answer:
(a) No. e.g., are isobars having same atomic mass but different atomic numbers. When atomic number is different it implies that they are different elements.
(b) (i) An isotope of cobalt (CO – 60) is used in the treatment of cancer.
(ii) An isotope of iodine (1 – 131) is used in the treatment of goitre.
OR
(a)
(i) Ensuring proper balanced diet.
(ii) Maintaining personal and public hygiene.
(iii) Isolation from other member if disease is contagious.
(iv) Proper bed rest and avoiding all type of mental stress.
(v) Maintaining healthy surroundings full of congenial (happy) atmosphere.
(vi) Providing vaccination to prevent further damage and supplements of vitamins and minerals to build immunity against future attack.
(b)
(i) To kill the cause of disease by using antibiotics which can kill the disease causing microbes.
(ii) To reduce the effects of the disease by giving treatment which can reduce the symptoms.
e.g., we can take medicines that bring down fever, reduce pain or loose motions.
Question 7:
Complete the following table :

Atomic number	Mass number	No. neutron	No. of protons	No. of electrons	Name of the atomic species
–	24	12	12	–	–
17	–	18	–	–	Chlorine

Answer:

Atomic number	Mass number	No. of neutron	No.of protons	No. of electrons	Name of the atomic species
12	24	12	12	12	Magnesium
17	35	18	17	17	Chlorine

Question 8:
Explain the following terms in brief:
(a) Bilaterally symmetrical
(b) Triploblastic
(c) Coelom
OR
Differentiate between the following (any one point):
(a) Diploblastic and Triploblastic
(b) Monocots and Dicots
(c) Warm blooded and Cold blooded animals Answer:
(a) It means that, the left and the right halves of the body have the same design.
(b) The animals whose body tissues are derived from three layers of cells are called triploblastic.
(c) The true, internal body cavity in which well developed body organs can be accomodated is called coelom.
OR
(a)

Diploblastic	Triploblastic
The body is made of two layers of cells (ectoderm and endoderm). e.g., Hydra, Jelly fish and Sea anemone.	The body is made of three layers of cells (ectoderm, endoderm and mesoderm). e.g., Platyhelminthes, Nematoda and all higher phylums.

(b)

Monocots	Dicots
(i)They have only one cotyledon in the seeds,	(i) They have two cotyledons in the seeds,
(ii) The flower of monocots is (rimerous (multiple of three) and leaf shows parallel venation. e.gv Grass, wheat, maize, rice, etc	(ii) The flower of dicots in pentamerous (multiple of 5) and leaf shows reticulate venation. e.g., Pea, pulses, mustard, etc.

(c)

Warm blooded animals	Cold blooded animals
(i) Their body temperature remains constant irrespective of their surroundings.	(i) Their body temperature changes according to the temperature of the surroundings.
(ii) They are also known as homeothermals and have energy requirements. e.gv Aves and mammals.	(ii) They are also known as poikilothermals and have low energy requirements, e.g., Pisces, amphibians and reptiles.

Question 9:
Area of bottom of a boat is 6 m2 it is floating on water. The boat sinks by is 1 cm, when a man gets on it. What is the mass of the man ?
Answer:
A = 6 cm²
Floating of water
Weight of boat = Buoyant force
mg = vdg; m = vd = 0.06 × 1000 = 60 kg [ v = A × Depth = 6 × 0.01 – 0.06 m³]
Question 10:
(a) A horse exerts a pull on a cart of 300 N. This makes the horse – cart system move with a uniform speed of 18 km h’1 on a level road. Calculate the power developed by the horse in watt.
(b) Prove that the total energy at any point in the path of a dropped mass is ’mg’ times the height from where it is dropped.
Answer:

Question 11:
(a) What do you mean by a pure substance ? Give an example.
(b) Name the appropriate methods to separate the following :
(i) Nitrogen from air
(ii) Dye from blue ink
(iii) Butter cream from milk
(iv) Ammonium chloride from common salt.
Answer:
(a) Pure substance : A pure substance contains only one kind of atoms or molecules and is homogeneous throughout its mass. A pure substance has a fixed composition as well as a fixed melting and boiling point, e.g., iron, water, etc.
(b)
(i) Fractional distillation
(ii) Chromatography
(iii) Centrifugation
(iv) Sublimation
Question 12:
Complete the following flow diagram:

Answer:
(a) Permanent tissue
(b) Lateral meristem
(c) Intercalary meristem
(d) Complex permanent tissues
(e) Sclerenchyma
(f) Phloem
Question 13:
Derive following equations for a uniformly accelerated motion :
(i) v = u + at (ii) S = ut + l/2at2, where symbols have their usual meaning.
Answer:
Suppose, the initial velocity of a body is u and it is moving with uniform acceleration a for time t. Let the final velocity be v and the distance covered be S. Then, we have .

Question 14:
Neem and turmeric powders are often used in grain storage.
(i) What are they called?
(ii) What is the purpose of using neem and turmeric?
(iii) What are herbicides?
Answer:
(i) Bio-pesticide.
(ii) Neem and turmeric keep away insects, rodents, fungi, mites, bacteria etc. from the stored foods.
(iii) Herbicides are chemicals used for removal of weeds from cultivated fields during the early
stages of crop growth.
Question 15:
Shruti went to a hill station with her parents and her elder brother Rushil. One day they were walking through a valley where Shruti and her brother started playing. Shruti was surprised to distinctly hear the same sound twice. She discussed it with her brother. He told her that this phenomenon is called ’echo’.
(a) Define echo. What should be the minimum distance from the source for a distinct echo to be heard
(b) Write the values shown by Rushil?
Answer:
(a) Echo: It is the phenomenon of reflection of sound of a source from an obstacle. Minimum distance – 17.2 m
(b) Values shown by Rushil are – ready to listen to scientific facts, good listener.
Question 16:
(a) Give reason for the following :
(i) Why does a desert cooler cool better on a hot dry day ?
(ii) Why do we prefer to wear cotton clothes during summer ?
(b) Write any three differences between evaporation and boiling.
Answer:
(i) The humidity, i.e., the amount of water vapour in air is less on a hot dry day. Lesser the humidity, more is the rate of evaporation. Since the rate of evaporation is more on a hot dry day, a desert cooler cools better.
(ii) We perspire more during summer. Cotton is a good absorber of water. It absorbs sweat and exposes it for easy evaporation. As a result body feels cool and comfortable. So, we should wear cotton clothes during summer.
(b)

Boiling	Evaporation
(i) Boiling is a bulk phenomenon,	(i) Evaporation is a surface phenomenon.
(ii) Particles from the bulk of the liquid change into vapour state.	(ii) Particles from the surface gain enough energy to overcome the jntermolecular forces of attraction present in the liquid and change into the vapour state.
(iii) Boiling starts at boiling point of a substance.	(iii) Evaporation starts below the boiling point.

Question 17:
(i) Identify in the situations given below where the object is making a uniform circular motion:
(a) A car turning around a curve with uniform speed. A car going uphill.
(b) Motion given to a discus by an athlete before releasing it. Motion of discus when the athlete releases it.
Give reason for your answer.
(ii) A cyclist completes five rounds of a circular track of radius 21 m in 12 minutes. Calculate his speed.
(iii) An artificial satellite moves around the earth with a velocity of constant magnitude, still its motion is said to be an accelerated motion, why ?
Answer:

(iii) Satellite is moving in a circular orbit with constant magnitude of velocity but its direction of motion is changing continuously, therefore, its motion is accelerated as the velocity changes in direction.
Question 18:
(a) How layers are different from broilers ? Give at least three differences between the two.
(b) What is composite fish culture system ? State one merit and one demerit of such a system.
Answer:
(a)

Layers	Broilers
(i) Layers are egg-laying chickens, managed for the purpose of getti ng eggs. (ii) Layers start producing eggs at an age of 20 weeks. So, they are kept for longer period depending upon laying period (approx. 500 days). (iii) They require enough space and adequate lighting.	(i) Broilers are maintained for getting meat. (ii) They are raised up to 6-7 weeks in poultry farms and then sent to market for meat purposes. (iii) They require conditions to grow fast and low mortality,

(b) A combination of five or six species raised in a single fishpond is called composite fish culture. Merit: The fishes raised have different food habits. So, these do not compete with each other for food. This increases fish yield.
Demerit: Many of these fishes breed only during monsoon.
Question 19:
(a) Name the international organization who approves names of elements.
(b) Give an example with explanation to show that the Law of conservation of mass applies to physical changes also.
Answer:
(a) IUPAC (International Union of Pure and Applied Chemistry).
(b) Law of conservation of mass states that “mass can neither be created nor destroyed in a – chemical reaction.”
This law applies to physical changes also.
e.g., During interconversion of water into three states of matter there is no change in the mass of water taken although there is change in the three states.

Question 20:
Give reasons:
(a) Animals of phylum platyhelminthes are called flatworms.
(b) Bryophytes are called amphibians of the plant kingdom.
(c) Fungi are called saprophytes.
(d) Bacteria and tapeworms are very different in their body design.
(e) Plants like Pinus and Deodar are called gymnosperms.
Answer:
(a) Because they show such body design which is dorsiventrally flattened.
(b) Because they can live both on land and in water but they require water for fertilization as their gametes are non-motile.
(c) Because they use decaying organic material as food.
(d) Because bacterial belongs to kingdom monera and these organisms do not have a defined nucleus or organelles whereas tapeworm belongs to phylum platyhelminthes whose body is triplastic, bilaterally symmetrical, complex with true internal body cavity called coelom.
(e) Because they bear naked seeds and are usually perennial, evergreen and woody which are the features of gymnosperms.
Question 21:
(a) State Archimedes’ principle.
(b) It is easier to swim in sea water than in river water. Why ?
(c) Give any two important applications of Archimedes’ principle.
(d) What do you mean by relative density of a substance? What is its unit ?
OR
(a) Define power. Give its unit.
(b) A moving body of mass 20 kg has 40 Joules of kinetic energy. Calculate its speed.
(c) A person carrying a load of 20 kg climbs 4 m in 10 seconds. Calculate the work done and his power, (g = 10 m s^-2)
Answer:
(a) Archimedes’ principle : When an object fully or partially immersed in a fluid, it experiences an upward thrust which is equal to the weight of fluid displaced by it.
(b) Because of higher density.
(c) 1. To check the purity of sample of milk.
2. To find the density of liquid.
(d) Relative density : It is the ratio of density of substance to the density of water. Units – It has no units
OR

SECTION – B
Question 22:
(a) Mention the type of thermometer that should be used to determine the melting point of ice
in laboratory.
(b) While doing an experiment to determine the melting point of ice, state the role of glass stirrer.
Answer:
(a) Laboratory thermometer with minimum range of -10°C.
(b) Glass stirrer is used to mix the ice and ice cold water thoroughly to get a uniform temperature.
Question 23:
A substance ‘X’ was taken and was added to distilled water. On stirring thoroughly the aqueous solution was left to stand for sometime. It was observed that its particles began to settle at the bottom. By this information what do you infer about the solution? What would happen if a beam of light is passed through this solution ? Answer:
(i) The given solution is a suspension.
(ii) Light does not pass through and no Tyndall effect is observed.
Question 24:
List two precautions to be taken while you determine the mass percentage of water imbibed by raisins.
Answer:
(i) Only clean raisins should be used for the experiment.
(ii) Petri dish should be left undisturbed.
Question 25:
In a spring balance the space between 0 to 25 g wt is divided into 5 equal parts. Find its least count. What is the weight of the object in the diagram given below ?
Answer:

Question 26:
An object of volume 25mL suffers a loss in weight of 15 gwt when immersed fully in a solution. Find the density of the solution.
Answer:
Question 27:
(a) Why the body of bony fish is streamlined 1
(b) List two habitats of bony fish.
Answer:
(a) To reduce friction while swimming. It means that it offer least resistance to motion while swimming.
(b)
(i) Ponds
(ii) Lakes
(iii) Rivers
It’s habitat includes shallow water, having less salt concentration (known as fresh water) and higher levels of dissolved oxygen.
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