SA2SETISCI0715AK 06-03-16
SUMMATIVE ASSESSMENT- II (2015-2016)
Grade VII(Science) – Answer Key
Section : A
I Fill in the blanks: (1x10=10)
1. Solenoid
2. Conductors
3. Rectilinear Propagation of light
4. Center of Curvature
5. Prism
6. Hemoglobin
7. Diffusion
8. Left
9. Galvanization
10. Carbon dioxide
II Match the following: (1x5=5)
1-d, 2-e, 3-a, 4-c, 5-b
III MCQ - Choose the correct option: (1x15=15)
1 - a (Concave mirror)
2 - a (Equal to incidence angle)
3 – a (Brown)
4. - c (Addition of oxygen or removal of hydrogen)
5 - b (Pointing downwards)
6 – a (Evaporation)
7 – c (Oxygen and water)
8 – b (Veins)
9 – b (Ascent of sap)
10 – c (Stethoscope)
11 – c (Platelets)
12 – a (Protein)
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13 – a (Conductor with low
melting point)
14 - b(Potential difference)
15 - b(Magnetic effect of
the solenoid)
SECTION – B
SUBJECTIVE PART
IV. Define the following (2 x 3 = 6)
1. Reduction Reaction: It is a chemical reaction that involves addition of
hydrogen or removal of oxygen from a substance.
2. Filament: is thin wire that glows in the bulb when current passes through it.
3. Translocation: The food prepared by the leaves is transported to all parts of
the plants in the form of a solution through a process known as translocation.
V. Differentiate: (write 2 points each and each point carries one mark) (4 x 4 = 16)
1. Exothermic reaction – (1) accompanied with release of heat (2) Release of
heat is shown by writing ‘+ heat’ on right hand side of the equation.
(3) All burning reactions are exothermic.
Endothermic reaction – (1) Reactions accompanied with absorption of heat.
(2) Absorption of heat is shown by writing ‘- heat’ on right hand side or
‘+ heat’
2. Real image: (1) Can be formed on screen
(2) It is inverted.
Virtual image: (1) Cannot be formed on a screen
(2) It is erect.
3. Arteries: (1) Carries blood away from the heart
(2) Have thick elastic walls
Veins: (1) Carry the blood back to the heart
(2) Have thin walls or
(3) They have valves, which allows the blood to flow only towards the heart
4. Xylem – (1) Transports water and minerals in the plants. (2) It transports
water and minerals in upwards direction only.
Phloem – (1) Transports food to all the parts of the plant. (2) Food goes from
tip of the shoot to the tip of the root in all the directions.
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VI. Give reasons for the following (2 x 4 = 8)
1. Fuse wires or MCBs are not used in a circuit containing electric cells –
because electric cells give very less current in the circuit.
2. An examination of urine is useful to the doctors because it tells a lot about
whether various organs in the body are functioning normally, the doctor
therefore uses the urine test to diagnose diseases in the body.
3. In Mumbai rusting will be more because rusting occurs in the presence of
both oxygen and water. The more humid the air faster the rusting occurs.
4. Convex mirrors are used as rear view mirrors in vehicles because Since a
convex mirror forms smaller images of objects, it can be used to view a
much large area than would be possible with the plain mirror.
VII. Short answers question (2 x 5 = 10)
1. It is a switch that automatically stops the current in a circuit if the current in
it exceeds the specific maximum limit.
2. If a person’s kidneys are damaged, doctors remove body waste by a medical
process known as dialysis.
3. (1) Virtual
(2) Erect
(3) Of the same size as the object
(4) Appears to be as much behind the mirror as the object is in front of it.OR
(5) Laterally inverted
4. Explain in detail the steps involved in preparing the base magnesium
hydroxide from the metal magnesium. (Write the equation for both steps.)
Step – 1: Magnesium reacts with oxygen on heating to form magnesium
oxide ---- 2Mg + O2 2MgO.
Step – 2: Magnesium Oxide dissolved in water, it forms magnesium hydro
oxide 2Mg + 2H2O 2Mg (OH)2
5. (i) Double displacement reaction.
(ii) Combination reaction.
VIII. Diagram based questions. (6+4=10)
a. Labeling (2 MARKS) each diagram and Show the position of principal focus ( F) in both
the diagrams.(Draw incident and reflected rays) one mark each.
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b. Label the given diagram of human excretory system:( one mark each)
A - Kidney
B - Ureters
C – Urinary Bladder
D - Urethra
IX. (i) Draw a labeled diagram of An Electric Bell.( drawing 3 marks and (3+4+3=10)
labeling any 4 parts of one mark each)
Explanation – 3 Marks
(ii) When current flows in the electromagnet, it attracts the iron rod
towards itself, causing the hammer to strike the gong.(1 ) At the same
time the armature loses contact with the screw and the current is
switched off.(1) This causes electromagnet to lose its magnetism and
the armature spring back to its original position to close the circuit
once again. This cycle repeats itself till the current is switched off.(1)
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