SEE (Secondary Examination Board)
Subject: Science & Technology
Model Set 2 Solution
RE-1041
SEE 2080 (2024)
Science & Technology
Time: 3 Hrs. Full Marks: 75
Write an answer in your own creative way on the basis of given instructions.
(Group ‘A’)
Multiple choice question: 10x1=10
1. Write the correct alternative of the following questions in the answer sheet.
a) Which of the following is the function of receiver?
To convert received signal into desired form.
b) Why are mosses and ferns both found in moist and shady places?
Requires water for fertilization.
c) When Samira observed specimen in the laboratory, she found that both the organisms were long and cylindrical. She also found that organism A has cylindrical segmented body and organism B has not segmented body. By studying the above characteristics which statement is true for these organisms?
Organism A has well developed circulatory system whereas organism B has no circulatory system.
d) Which of the following groups is a group of endangered animals?
Black buck, Wild yak, One horned Rhinoceros.
e) The acceleration due to gravity on the surface of the earth is g. If mass and radius both are made halved, what is the new value of acceleration due to gravity on the earth surface?
Given,
Case-I
Acceleration due to gravity = g
Let mass of the earth be ‘M’, radius of the earth is ‘R’ and universal gravitational constant is ‘G’.
We have
Case II
Mass of the new earth = M/2
Radius of the new earth = R/2
New acceleration due to gravity =
f) On which principle given instrument based on?
Pascal’s law
g) Soni named the speed of violet, blue, yellow and red coloured beam during dispersion of light in prism as ev, eb, ey and er respectively. Which is the correct order of speed made by her?
er > ey > eb > ev.
h) Under what condition can the flat universe be hypothesized?
When average density is equal with the critical density.
i) What is X in the given chemical equation?
NaOH + X à NaCl + H2O
HCl
j) Organic matter is considered as a major source of water pollution caused by wastes of food, animal and human excreta, garbage etc. Which of the following is a threat to aquatic life due to the excess of organic matter in water?
Microorganisms consume dissolved oxygen to decompose organic matter.
(Group ‘B’)
2. Write very short answer of the following questions: 9x1=9
a) What is dependent variable? Write with an example.
A dependent variable is the factor or condition that we measure or observe in an experiment. For example, plants grow faster in warmer temperature. Here, growth of the plant is dependent variable.
b) Write the relation between upthrust and weight of displaced liquid.
Upthrust and weight of displaced liquid are equal.
c) The apparent depth of water in a pond appears less than the real depth. Why?
The property of light is the refraction of light because when light travels from a denser medium to rarer medium it bends away from the normal. The apparent depth of water is always less than the real depth of the water. Hence, water appears to be shallower than the real depth.
d) What is the focal length of lens having power 1 dioptre?
Given
Power of lens (P) = 1D
Focal length(f) = ?
Power = 1/ f(in m)
Or, 1D = 1/ f(in m)
Or, f = 1/1
Or, f = 1m
e) A fan in a room rotates when its switch is made on which principle is used here?
It is based on the motor effect.
f) Which force is responsible for the existence of heavenly bodies in the universe?
Gravitational force is responsible for the existence of heavenly bodies in the universe.
g) Write the name of main ore of iron.
The main ore of iron is hematite.
h) Why reduction of active metal is possible only by the electrorefining method?
It is because it is cheaper and easier than chemically separating the desired material from the impurities.
i) Write molecular formula of given compound.
The molecular formula of given compound is C3H6. It is propene.
(Group ‘C’) 14x2=28
Write short answer questions.
3. Prove that the unit of potential difference (V) = kgm2s-3A-1.
Let potential difference be ‘V’.
Hence, it is proved.
4. Write any two characteristics of gymnosperm.
Any two characters of gymnosperm are:
a) They have naked seeds.
b) They bear cones instead of flower.
5. Which process is represented by A and B.
A is parthenogenesis B is fertilization.
6. Write any two differences between diploid cell and haploid cell?
|
S.No. |
Diploid cell |
S.No. |
Haploid cell |
|
01. |
The chromosomes are in pair. |
01. |
The chromosomes are not in pair. |
|
02. |
They are formed after mitosis cell division. |
02. |
They are formed after meiosis cell division. |
7. In which two conditions in vitro fertilization helps for reproduction in women?
In following two conditions invitro fertilization helps for reproduction in women:
a) If the fallopian tube is blocked.
b) If the women have advanced menstrual cycle.
8. Valves are present in veins but not in arteries, why?
The rate of flow of blood and blood pressure both are high in
arteries. There is no chance of backflow of blood in the arteries. But
in veins, the rate of flow of blood and blood pressure both are less.
There is chance of backflow of blood. So, valves are present in veins
but not in arteries.
9. Study the given figures alongside.
a) Write an importance of a plant given in figure (a).
It is neem plant (Azadirachta indica). It is used to cure skin problems.
b) Which part of the plant given in figure (b) is more useful?
Figure (b) is turmeric (Curcuma loga). Its rhizome is important.
10. Give any two examples of free fall.
Any two examples of freefall are:
· An stone dropped down an empty well.
· An object, in projectile motion, on its descent.
11. A body is dropped from top of the tower of height 'h' and at the same time next body is thrown up from the bottom of tower with velocity 20m/s. If these bodies meet after 2 sec. at a point of the tower, calculate the height of the tower. (g = 10m/s )?
Let us assume that two bodies meet at a height ‘x’ after 2 seconds.
Given,
While dropping down
Initial velocity (u) = 0m/s
Time (t) = 2 seconds
Distance(s) = h-x
We have
12. Write an application of step up transformer and step-down transformer each.
An application of step-up transformer is, it is used to increase the AC voltage in the hydro power plant. An application of stepdown transformer is to reduce the AC voltage like, the mobile chargers work. A mobile charger is a step down transformer.
13. The coil of the AC generator is shown in the diagram. Write any two ways of increasing the amount of induced electromotive force.
The two methods to increase the amount of induced electromotive force in an AC generator are as follow:
a) By increasing the strength of magnet used.
b) By decreasing the distance between magnet and the coil.
14. Suppose equal volume of hydrogen peroxide is kept in conical flask P and Q. If some amount of MnO2 and H3PO4 are kept in P and Q respectively, in which conical flask rate of chemical reaction is faster? Write with reason.
The rate of chemical reaction is faster in conical flask P because MnO2 is a positive catalyst. In this case, MnO2 provides an alternative pathway for the reaction to occur, lowering the activation energy and accelerating the decomposition of H2O2. H3PO4 (Phosphoric Acid). This acts as an inhibitor for the decomposition reaction. Inhibitors slow down the reaction rate.
15. A hydrocarbon compound 'A' is used to preserve biological specimen and next hydrocarbon 'B' is used as sweetening agent in confectionery. Answer the following questions.
a) Write down IUPAC name of compound 'A'.
The IUPAC name of compound A is ethanol.
b) Write the structural formula of compound 'B'.
16) Write any two applications of Calamus in daily life?
Any two applications of Calamus in daily life are:
a) It is used to cure cough and cold.
b) It is used to cure digestive disorders.
(Group ‘D’) 7x4=28
17) Study the figure and answer the following questions.
a) Write any two examples in which above technology is used.
This technology is used in mobile phones and satellite TV.
b) Write the function of transmitter and receiver.
The transmitter delivers the carrier signal modulated by information through an antenna. The receiver recovers the information from the received signal from the antenna.
18) A family has got only two daughters. Does it mean that the husband does not produce sperm bearing 'Y' chromosome? Explain it by showing sex determination chart.
Sex of the child depends upon the kind of sperm that fertilizes the egg.The egg contains only one X chromosome, but half of the sperms released into the female are X-bearing and the remaining half are Y-bearing.It is simply a matter of chance as to which category of sperms fuses with the ovum.If the egg (X) is fused by X-bearing sperm, the resulting combination is XX, i.e. female type, and the child produced is female (daughter).If the egg (X) is fused by Y-bearing sperm, the resulting combination is XY, i.e. male constitution, and the child produced will be a male (son).So, it does not mean that the husband does not produce Y-bearing sperms.
19) The composition of blood is shown in the given figure. Answer the following questions.
i) Write the name of B.
B is WBC(White Blood Cells)
ii) Which disease may occur if number of A is less
in blood?
A is RBC. If A is less, anaemia is caused.
iii) What is the main function of C?
C is platelets, the main function of platelets is to clot the blood
during bleeding.
iv) What is the life span of B?
The life span of B is about 15 days.
20) Study the given table and answer the following questions.
|
Metal |
Specific heat capacity (J/Kg0C) |
|
A |
234 |
|
B |
400 |
|
C |
900 |
a) Which one gets cooled faster, if equal mass of these three metals are heated to maintain the same temperature and then they are exposed in the air? Why?
Given,
Mass = m, heat energy = Q , specific heat capacity =s, difference in temperature = dt
We have
Q = msdt
M and dt are constants. Removing the constants
Q α s
Heat energy is directly proportional to specific heat capacity.
Hence, A cools down faster.
b) Which one of these three metals of same masses need more heat energy to maintain same temperature? Why?
We have,
Q =msdt
m and dt are constants.
Removing constants
Q α s
Heat energy is directly proportional to specific heat capacity.
C needs more heat energy to maintain the same temperature.
21) A man can read books only keeping away from his eye. Answer the following questions on the basic of this fact.
a) What is the type of defect of vision of eye?
He is suffering from hypermetropia.
b) Write one cause of this defect of vision.
One major cause of this defect of vision is thickening of eye ball.
c) What suggestion do you give to remove this defect?
He should use convex lens of suitable focal length to remove the defect.
d) Draw a diagram showing the correction.
22) Atoms of eight elements A, B, C, D, E, F, G and H have equal number of orbits but different number of valence electrons. Elements A and G combine to form an ionic compound. It is used to add in vegetables at the time of cooking food. Oxides of elements A and B are basic while E and F are acidic. The oxide of D is neutral. Based on this information, answer the following questions. Na Cl 2,8,1 2,8,7
a) To which period of modern periodic table do the listed elements belong?
The period is 3.
b) Write the symbols of highly reactive metal and highly reactive non metal from the listed elements.
The symbol of highly reactive metal is Na and highly reactive non metal is Cl.
c) Write the symbol of element that does not take part in chemical reaction.
The symbol of element that does not take part in chemical reaction is Ar.
d) Write an important difference between B and F.
B is magnesium and F is sulphur. Magnesium is a metal whereas sulphur is a non-metal.
23) Draw a well labeled diagram of laboratory preparation of carbon dioxide gas. How is this gas tested by using litmus paper? Explain.
dil. 2HCl + CaCO3 → CaCl2 + CO2 + H2O
Since, it is an acidic gas, it converts moist blue litmus paper to red. This is a method to test this gas.
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