SAMPLE QUESTION PAPER – 1
Class – X
Session: 2021-22 (TERM II)
Subject: Science
Time Allowed: 120 minutes Maximum Marks: 40
General Instructions:
1. All questions are compulsory.
2. The question paper has three sections and 15 questions. All questions are compulsory.
3. Section–A has 7 questions of 2 marks each; Section–B has 6 questions of 3 marks each; and Section–C has 2 case-based questions of 4 marks each.
4. Internal choices have been provided in some questions. A student has to attempt only one of the alternatives in such questions.
SECTION A
1. (a) The diagram shows the structure of a carbon compound-
How many bonding pairs of electrons are there in the molecule?
17
(b) C4+ does not exist but Pb4+ exists although both belong to the same group. Why?
Size of C is much smaller as compared to Pb and from a nucleus having 6 protons, it is very difficult to remove 4 electrons as a large amount of energy is required for this purpose
2. Consider the given section of the periodic table
Identify A, B, C and D
A- Na, B- Ca, C- B, D-Ge
OR
a. Arrange the following in the increasing order of their relative sizes- A–, A+, A
A+ < A < A
b. How many periods and group are present in the modern periodic table?
Periods= 7, Groups = 18
3.
The given diagram represents P and Q fusing to give R. This R then produces S, T, U and V. What do P, Q , R and S represent here ?
P, Q –gametes- Male, Female, R –Zygote, S- Embryo
4. Which part of the diagram below represents conditions which are necessary to activate enzymes when a seed germinates? Justify your answer.
B, The seed usually germinates in the soil where light is not needed. However, suitable temperature and water both are needed providing favourable conditions for seed to germinate by activating the enzymes.
5. A blue colour flower plant denoted by BB is crossbred with that of white colour flower plant denoted by bb.
a. State the colour of flower you would expect in their F2 generation plants.
All the flowers in the F1 generation are blue
b. What must be the percentage of white flower plants in F2 generation if flowers of F1 plants are self-pollinated
If flowers of F1 plants are self-pollinated
6.
A copper wire is held between the poles of a magnet. The current in the wire can be reversed. The pole of the magnet can also be changed over. In how many of the four directions shown can the force acts on the wire?
As per Fleming’s left hand rule – Two possibilities for the direction of the force- upward& downward
OR
How will you find the direction of magnetic field lines in a straight current carrying conductor? Explain.
One can find the direction by using right hand thumb rule which state that if thumb of the right hand points along direction of current, then the remaining curled, fingers of same hand gives the direction of the magnetic field due to the current.
7. The diagram shows the flow of energy through an ecosystem.
The smallest amount of energy transferred between organisms and the largest amount of energy lost to the ecosystem is represented by which arrows? Explain with an example.
B, C
About 90% of the chemical energy received by the rabbit is utilized for the metabolic activities and lost as heat and undigested matter. Only 10% is used for the growth and formation of new tissues.
OR
a. The presence of some chemicals in the air is the main cause of decrease in ozone in stratosphere. Name such chemical.
CFC
b. Why do scientists think that human – induced global warming will be more harmful to plants and animals, than were past -natural climate fluctuations?
Because temperatures changing faster
SECTION B
8. An element X combines with hydrogen to form a compound XH3. The element X is placed on the right side of the periodic table
a. State –
i. Whether it is metal or non-metal
Non-metal
ii. The number of its valence electrons
5
b. Which element is this?
N
9. Define homologous series of carbon compounds. List its two characteristics. Write the name and formula of the first member of the series of alkenes.
A series of hydrocarbons which have similar chemical properties and they share the same general formula. They have similar structure and functional groups, show gradation in physical properties. Ethene, C2H4
OR
a. What are isomers? Draw the structures of two isomers of butane, C4H10.
The organic compounds having the same molecular formula but different structures are known as isomers. Isomers of butane, C4H10:
b. Why can’t we have isomers of first three members of alkane series?
Isomerism is not possible in first three members of alkane series (i.e., methane, ethane, propane) because they contain only one, two or three carbon atoms respectively and with only 1, 2 or 3 carbon atoms, it is not possible to have different arrangements of carbon atoms.
10. With the help of an example justify the following statement:
“A trait may be inherited, but may not be expressed.”
In Mendel’s experiment with pea plants, when he cross-bed a tall pea plant with a short plea plant, he found that the first generation (F1) was of only tall plants. In the F1 progeny, no short plants were obtained. However, in the F2 generation, both tall and short plants were obtained in the ratio 3 :1 respectively. In the F2 generation, both traits – tallness and shortness were inherited where the tall character was the dominant trait and short character was the recessive trait.
Conclusion. Reappearance of dwarf character in F2 generation proves that the dwarf trait was inherited but not expressed in the F1 generation.
OR
“The sex of a newborn child is a matter of chance and none of the parents may be considered responsible for it.” Justify this statement with the help of a flow chart showing determination of sex of a newborn.
If a sperm carrying X-chromosome fertilizes an ovum carrying X-chromosome, then the child born will be a girl.
Therefore, it is the sperm from the father which determines the sex of the child. Thus in human beings, the sex of the baby is determined by the type of sperm that fuses with ovum. As human male produces two types of sperms in equal proportion, so there are 50% chances of a male baby and 50% chances of a female baby.
11. Match the following
A – ii, iv
B – i
C – iii
12. How much work is done in moving a charge of 2C from a point of 118V to a point of 128V?
W=10×2=20J
a. Bending of a wire does not affect its electric resistance. Explain it.
R= ₰. L/A
b. Two unequal resistances are connected in parallel. What would you say about potential difference across the both?
Potential difference is same across the both
c. A student carries out an experiment and plots the V-I graph as shown above of two samples of nichrome wire A and B, having resistances RA and RB respectively. Which wire has greater resistance?
wire B
13. Give reasons
a. Flow of energy in a food chain is unidirectional.
Energy captured by autotrophs does not revert back to the solar input and it passes to the herbivores.
b. Replacing of plastic cups for selling tea on train is preferred.
paper cups are biodegradable and eco – friendly.
c. The concentration of harmful chemicals is more in human beings.
Man is at the apex of the food chain. Harmful chemicals accumulate progressively at each trophic level.
SECTION C
This section has 02 case-based questions (14 and 15). Each case is followed by 03 sub-questions (a, b and c). Parts a and b are compulsory. However, an internal choice has been provided in part c.
14. Refer to the given table regarding results of F2 generation of Mendelian cross.
a. Which would be the phenotype of F1 generation regarding given data of F2 generation?
Plants with round and yellow coloured seeds
b. Which would be the genotype of parental generation regarding given result of F2 generation?
YYRR and yyrr
c. What are gametes? How many types of gametes can be produced by YYrr?
Gametes are an organism’s reproductive cell/sex cell, one
OR
Calculate the percentage of yR gamete produced by YyRR parent.
50% plants with wrinkled and yellow coloured seeds and 50% plants with wrinkled and green coloured seeds
15. Anshu described the magnetic field of a magnet by drawing the magnetic field lines. When he placed a small north magnetic pole in the magnetic field created by the magnet, and it experienced a force. When the north pole was free, it moved under the influence of magnetic field.
The path traced by a north magnetic pole free to move under the influence of a magnetic field is called magnetic field line.
Now answer the following questions on the basis of his observation
a. What do the magnetic field lines determine?
They determine both the direction and the relative strength of the magnetic field.
b. Anshu further placed a strong bar magnet vertically above a horizontal wooden board. What would be the position of the magnetic lines of force?
They would be on the all the planes around the magnet
c. Draw magnetic field lines of a bar magnet.
OR
The magnetic field lines do not cross each other. Why?
If two field lines crossed each other, it would mean that at the point of intersection, the compass needle would point in two directions at the same time, which is not possible.