Please refer to Class 10 Science Sample Paper Term 1 Set C with solutions below. The following CBSE Sample Paper for Class 10 Science has been prepared as per the latest pattern and examination guidelines issued by CBSE. By practicing the Science Sample Paper for Class 10 students will be able to improve their understanding of the subject and get more marks.
CBSE Class 10 Science Sample Paper for Term 1
Section – A
1. A functional group is a group of atoms in a molecule with distinctive chemical properties, regardless of the other atoms in the molecule. The atoms in a functional group are linked to each other and to the rest of the molecule by covalent bonds. Write the names of functional group of the compounds given below:
(a) CH3−COOH
(b) CH3−CH2−CH2−OH
Ans. (a) –COOH group: Carboxylic acid
(b) –OH group: Alcohol
2. The atomic radii of first group elements are given below:
(a) State the reason behind the observed trend in the above elements.
(b) How does valency of an element vary across a period?
Ans.(a) In a group, as we move from top to bottom, the number of shells increases. Hence, the atomic radius increases.
(b) The valency of an element first increases and then decreases across a period.
3. (a) What is meant by vegetative propagation?
(b) How will a plant be benefitted if it reproduces by this method?
Ans.(a) Vegetative propagation is a form of asexual reproduction that occur in plants in which new plants are produced by vegetative parts such as the roots, stems and leaves.
(b) Plants raised by vegetative propagation can bear flowers and fruits earlier than those produced from seeds. Such method also makes possible the propagation of plants that have lost the capacity to produce seeds.
4. (a) Write one main difference between asexual and sexual mode of reproduction.
(b) Which species is likely to have comparatively better chances of survival-the one reproducing asexually or the one reproducing sexually? Justify your answer.
Ans. (a) In sexual reproduction, two parents (of opposite sex) are involved whereas in asexual reproduction, only one individual parent is involved.
(b) In sexual reproduction, male and female gamete formation takes place whereas in asexual reproduction, no gamete formation occurs. That is, sexual reproduction promotes diversity of characters in an offspring due to combination of genes which leads to variation whereas in asexual reproduction evolutionary change is not possible. Thus, sexually reproducing organisms have better chances of survival
5. Reema is doing a school project on evolution. She is confused in the scientific terms such as inheritance and heredity. Help her to find the correct answers for the scientific terms for the phenomena given below.
(a) The mechanism by which variations are created and inherited
(b) The development of new type of organism formed from the existing ones.
Ans. (a) Genetics is the study of mechanism by which variations are created and inherited
(b) Evolution is used for studying the development of new type of organisms from the existing ones.
OR
How do Mendel’s experiment show that traits are inherited independently?
Ans. (i) When a cross was made between a tall pea plant with round seeds and a short pea plant with wrinkled seeds, the F1 progeny plants were all tall with round seeds. This indicates that tall and round seeds are the dominant traits.
(ii) When the F1 plants are selfpollinated, the F2 progeny consist of some tall plants with round seeds and some short plants with wrinkled seeds which are the parental traits.
(iii) There were also some new combinations like tall plants with wrinkled seeds and short plants with round seeds.
(iv) Thus, it may be concluded thattall and short traits and round and wrinkled seed traits have been inherited independently.
6. It is established that an electric current through a metallic conductor produces a magnetic field around it. Is there a similar magnetic field produced around a thin beam of moving :
(a) alpha particle,
(b) neutrons?
Justify your answer.
Ans.(a) Yes, alpha particles being positively charged constitute a current in the direction of motion and magnetic field is produced.
(b) No. The neutrons being electrically neutral constitute no current and hence no magnetic field.
OR
In the given diagram, crosses Ä represent a uniform magnetic field directed into the paper. A conductor XY moves in the field toward right side.
(a) Find the direction of induced current in the conductor.
(b) Name the rule applicable here. Justify your answer.
Ans. (a) The direction will be from Y to X. By Fleming’s right hand rule the current will be induced in the upward direction (Y to X).
(b) Fleming’s right hand rule: Hold the thumb, the fore finger and the middle finger of right hand at right angles to each other. If the forefinger is in the direction of magnetic field and the thumb points in the direction of motion of conductor, then the direction of induced current is indicted by middle finger.
7. Ravi is eating curd/yogurt. For this food intake, which trophic level of the food chain he has occupied ? Who will be at the first trophic level in the food chain? Justify your answer.
Ans. Ravi belongs to third trophic level. Grass/ plants will be at the first trophic level. Curd is made from milk which is obtained from cow. Cow is a primary consumer that feeds onproducer such as grass/plants. So, the grass/ plants will be at the first trophic level as they are the producers. Cow feeds on them and occupies second trophic level. Consuming the product obtained from an organism at second trophic level makes Ravi occupy the third trophic level.
OR
From the following groups of living things:
(a) Create a food chain which is the most advantageous for human being in terms of energy.
(b) Construct a food web using the living things mentioned above.
Ans. (a) Short food chains are more efficient in terms of energy. The shorter the food chain is, more is the available amount of energy for human beings to utilize. Cereal plant → Human being
Section – B
8. An element ‘M’ has atomic number 12.
(a) Write its electronic configuration and valency.
(b) Is ‘M’ a metal or a non-metal? Give reason in support of your answer.
Ans. (a) Electronic Configuration — 2, 8, 2
Valency — 2.
(b) There are two electrons in the outermost shell of M and it easily loses them to form a positive ion. Thus, element M is a metal.
(c) M = 2
O = 2
Chemical formula M2O2 = MO
It is a basic oxide.
9. Give reason why carbon can neither form C4+ cations nor C4– anions, but forms covalent compounds. Also, state the reason to explain why covalent compounds are bad conductors of electricity and have low melting and boiling points ?
Ans. Carbon cannot form C4+ cation because removal of four electrons from a carbon atom would require a large amount of energy. Carbon cannot form C4– anion because it
would be difficult for the nucleus with 6 protons to hold on to 10 electrons. Hence, carbon atoms share electrons, forming covalent compounds.
Covalent compounds do not form ions/ charged particles and therefore do not conduct electricity.
Inter-molecular forces of attraction are weak, hence they have low melting and boiling points.
OR
Define the following compounds:
(a) Alkanes
(b) Alkenes
(c) Alkynes
Ans. (a) Alkane: Saturated hydrocarbon with C – C single bond with molecular formulaCnH2n+2
(b) Alkene: Unsaturated hydrocarbon with double bond in C = C with molecular formula CnH2n
(c) Alkyne: Unsaturated hydrocarbon with triple bond in C º C with molecular formula CnH2n–2
10. How many pairs of chromosomes are there in human beings? How is the sex of human offspring determined? Explain.
Ans. There is one pair of sex chromosomes present in human being.
The offspring receives one chromosome from each of the parents. Mother have a perfect pair of sex chromosomes (XX). But, father have a mismatched pair (XY). All children will inherit an X chromosome from their mother regardless of whether they are boys or girls. Thus, the sex of the children will be determined by chromosome they inherit from their father. child who inherits an X chromosome from her father will be a girl, and one who inherits a Y chromosome fromhim will be a boy.
11. (a) State the relation correlating the electric current flowing in a conductor and the voltage applied across it. Also, draw a graph to show this relationship.
(b) Find the resistance of a conductor if the electric current flowing through it is 0.35 A when the potential difference across it is 1.4 V.
Ans. (a) The flow of current (I) in the conductor is directly proportional to the potential difference (V) established across the conductor provided the physical conditions remain same. Mathematically, V = IR, where R is resistance of the conductor.
(b) Given:
Potential Difference (V) = 1.4 V
Current (I) = 0.35 A
As per Ohm’s law, V = IR
So, R =V / I = 1.4 / 0.35= 4 Ω
12. Help Sunita to find the readings of the ammeter and the voltmeter when key is closed? Justify your answer.
Ans. When resistances are connected in series,
Req = R1 + R2 + R3
R = 5 Ω + 8 Ω + 12 Ω
= 25 Ω
Given V = 6 V
By Ohm’s law, V = IR
∴ I = V / = 6V / 25 Ω
Ammeter reading = 0.24 A
The voltmeter is connected across the series combination of 8W and 12Ω.
So, the voltmeter reads
V’ = I x R’
= 0.24 x (8+12)
= 4.8V
OR
(a) Define electrical resistivity.
(b) Calculate the resistance of 1 km long copper wire of cross-section area 2 × 10–2cm–2.
[Resistivity of copper = 1.62 × 10–8Ω m]
Ans. (a) Electrical resistivity of the material of a conductor is the resistance offered by the conductor of length 1 m and area of cross-section 1m2.
(b)
13. The ozone layer is the common term for the high concentration of ozone that is found in the stratosphere around 15–30 km above the earth’s surface. It covers the entire planet and protects life on earth.
(a) Explain the role of UV radiation in producing ozone layer. Mention the reaction involved.
(b) Why the amount of ozone in the atmosphere dropped sharply in the 1980’s ?
Ans.(a) Ozone is formed in the upper atmosphere when solar UV radiation dissociate molecules of oxygen (O2) and then this oxygen atom (O) combines with an oxygen molecule. Reaction involved:
O2 → O + O
O + O2 → O3 2
(b) The amount of Ozone in the atmosphere began to drop sharply in the 1980s. This is due to the increased use of synthetic chemicals like chlorofluorocarbons which are used as refrigerants and in fire extinguishers.
Section – C
14. Seema crossed pure breed pea plants having round-yellow seeds with wrinkled green seeds and found that only A-B type of seeds were produced in the F1 generation. When F1 generation pea plants having A-B type of seeds were cross-breed by self-pollination, then in addition to the original round yellow and wrinkled green seeds, two new varieties A-D and C-B types of seeds were also obtained.
(a) What type of seeds are A-B type of seeds?
(b) Which types of traits are A and B. Dominant or recessive?
(c) What type of cross is the above cross? Define the type of cross.
Ans. (a) A-B type of seeds are round in shape and yellow in colour.
(b) A-B type are dominant traits.
(c) Dihybrid cross. A cross between two plants, which differ in two pairs of contrasting characters are called dihybrid cross
OR
Differentiate gene and allele.
Ans. Allele (allelomorphs) refers to the alternate form of a gene pair present on the same loci in the homologous chromosome, whereas gene is the smallest unit of an organism capable of transmitting genetic information and expressing the same.
15. Richa is performing an experiment on magnetism for which she has used two magnets A and B. She felt that here was an attraction between the magnets. So, she drew the magnetic field lines as below. But her teacher said that the diagram was wrong.
(a) Why the diagram was wrong?
(b) Draw the correct diagram.
(c) What does the direction of thumb indicate in the right-hand thumb rule. In what way this rule is different from Fleming’s left-hand rule?
Ans. (a) From the drawing of Richa it is clear that the magnetic north poles are facing each other. But there was an attraction between the magnets. So, north pole of one magnet was facing the south pole of the other magnet.
(b) The correct diagram may be any one of the following two diagrams.
(c) In right hand thumb rule the right hand thumb rule thumb indicates the direction of current in the straight conductor held by curled fingers, whereas in Fleming’s left-hand rule the thumb gives the direction of force experienced by current carrying conductor placed in an external magnetic field.
OR
Meena draws magnetic field lines of field close to the axis of a current carrying circular loop. As she moves away from the centre of the circular loop she observes that the lines keep on diverging. How will you explain her observation?
Ans. Strength of the magnetic field decreases as distance increases. This is indicated by the decrease in degree of closeness of the lines of field.
