Class 10 Science Sample Paper Term 1 With Solutions Set B

Please refer to Class 10 Science Sample Paper Term 1 With Solutions Set B below. These Class 10 Science Sample Papers will help you to get more understanding of the type of questions expected in the upcoming exams. All sample guess papers for Science Class 10 have been designed as per the latest examination pattern issued by CBSE. Please practice all Term 1 CBSE Sample Papers for Science in Standard 10.

Sample Paper Term 1 Class 10 Science With Solutions Set B

Section – A

1. A covalent bond is formed by equal sharing of electrons from both the participating atoms. The pair of electrons participating in this type of bonding is called shared pair or bonding pair. Sharing of bonding pairs will ensure that the atoms achieve stability in their outer shell which is similar to the atoms of noble gases.

Class 10 Science Sample Paper Term 1 With Solutions Set B

(a) Why are covalent compounds generally poor conductors of electricity ?
(b) Name the following compound:

Ans. 1. (a) It is because they do not form ions.
(b) Propanone (Acetone)

2. The elements of the third period of the Periodic table are given below:

(a) Which atom is bigger, Na or Mg? Why?
(b) Identify the most (i) metallic and (ii) non-metallic element in Period 3.
Ans. (a) Sodium is bigger than magnesium as it has lesser nuclear charge. So, there is less force of attraction between nucleus and valence electrons and less effective nuclear charge. It is, therefore, bigger in size.
(b) (i) Sodium is the most metallic element in period 3, as it can lose electrons easily due to its larger atomic size.
(ii) Chlorine is the most non-metallic element in period 3, because, it can gain electrons easily due to its smallest atomic size.

3. In an experiment, a worm found in freshwater and slow-moving streams was cut into three pieces. It was observed that in due course of time, each cut piece of the worm develops to become a complete worm by growing all the missing parts.
(a) Identify the worm. Name another organism, which possesses the same characteristic of growing fully from its cut body parts.
(b) What is the name given to this type of reproduction? State whether the given organisms are unicellular and / or multicellular organisms.
Ans. (a) The worm is Planaria. An example of other organism is “Hydra”.
(b) The process is known as regeneration. The given organisms are multicellular organism.

4. Contraception is defined as the intentional prevention of conception through the use of various devices, sexual practices, chemicals, drugs, or surgical procedures. Thus, any device or act whose purpose is to prevent a woman from becoming pregnant can be considered as a contraceptive.
(a) Name any two contraceptive methods practiced only by women.
(b) How these contraceptive methods work?
Ans. (a) Oral pills and Loop/Copper-T are used by women only. 1
(b) (i) Oral pills change hormonal balance, so eggs are not released.
(ii) Loop/Copper-T are placed in the uterus. It prevents pregnancy by checking the entry of sperms through the vagina.

5. In a cross between plants with homozygous pink flowers and plants with homozygous white flowers, all the offsprings of F₁ generation had pink flowers. When the F1 generation was self-crossed, it was observed in the F₂ generation that out of 100, 75 flowers were pink. Make a cross and answer the following questions:
(a) What are the genotypes of the F₂ progeny?
(b) What is the ratio of Pink: White flowers in the F₂ generation?
Ans. (a) Genotypes of F₂ progeny are PP, Pp and pp.

(b) Ratio of pink and white flowers is: 3:1 1

‘Gene control traits’? Explain this statement with an example.
Ans. Genes are sections or segments of DNA that are carried on the chromosomes and determine specific human characteristics, such as height or eye colour. A gene codes for the formation of a particular protein which in turn controls the characteristics or traits. 1 For example: In pea plant, gene T is responsible for tallness of the plant. It gives instruction
to the plant to synthesize a particular plant hormone. The amount of the plant hormone made will depend on the efficiency of the enzymes that make it. Consider now an enzyme that is important for this process. If this enzyme works efficiently, huge amount of hormone will be made, and the plant will be tall. If the gene for that enzyme has an alteration that makes the enzyme less efficient, the amount of hormone will be less, and the plant will be short. Thus genes control the traits.

6. Garima Saini, performed an activity in school laboratory to observe the effects of magnetic field lines. Based on her observation, she has drawn the magnetic field lines of two magnets as shown in fig. A and fig. B.

(a) Select the figure that represents the correct pattern of field lines. Give reasons for your answer.
(b) Also, name the poles of the magnets facing each other.
Ans. (a) Figure B represents the correct pattern of field lines. In figure A, field lines cross each other which is not possible because if they cross each other, at the point of intersection, there would be two directions of field lines. 1
(b) In figure B, field lines are emerging in nature, so poles of magnet facing each other are north poles while opposite faces will have south polarity.

Identify the poles of the magnet in the given figures:

Ans. (a) Field lines emerge from north pole (N) and merge at the south pole (S) in figure (1), So the poles of the magnet are:

(b) Field lines emerge from north pole (N) and merge at the south pole (S) in figure (2), So the poles of the magnet are:

7. Let the amount of energy at fourth trophic level in the given food chain is 5 kJ, what will be the energy available at the producer level? Why do producers always occupy the first trophic level on every food chain?

Ans. In the given food chain, if the amount of energy at fourth trophic level is 5 kJ, then 5000 kJ will be the energy available at the producer level. It is because, according to 10% law, only 10% of energy is transferred to the next trophic level and remaining 90% energy is used in life processes by present trophic level.
Producers always occupy the first trophic level on every food chain because producers (plants) have the ability to trap solar energy with the help of chlorophyll.

The following organisms form a food chain.

Which of these will have the highest concentration of non-biodegradable chemicals? Name the phenomenon associated with it.
Ans. Hawk will have the highest concentration of non-biodegradable chemicals. The phenomenon associated with it is called biomagnification.

Section – B

8. Three elements are represented in the given periodic table:

By giving reasons, explain the following questions:
(a) Element A is non-metal.
(b) Atom of element C has a larger size than atom of element A.
(c) Element B has a valency of 1.
Ans. (a) It is because it has 7 valence electrons. It can gain one electron to form negative ion. So, it is a non-metal. 1
(b) ’C’ has more number of shells than ‘A’. So, it is larger in size. 1
(c) ’B’ has one valence electron. It can lose one electron to become stable. So, its valency is equal to 1.

9. (a) Elements that form ionic compounds attain noble gas electronic configuration by either gaining or losing electrons from their valence shells. Explain by giving reason why carbon cannot attain such a configuration in this manner to form its compounds.
(b) Name the type of bonds formed in ionic compounds and in the compounds formed by carbon.
Ans. (a) Carbon has 4 electrons in its outermost shell. It cannot lose 4 electrons to form C⁴⁺ as very high energy is required to remove 4 electrons from its valence shell.
It cannot gain 4 electrons to form C^4– as it is difficult for 6 protons to hold on to 10 electrons.
(b) In ionic compounds, ionic bonds areformed; while in carbon compounds, covalent bonds are formed.

(a) What are isomers? Draw the structures of two isomers of butane, C₄H₁₀.
(b) Why can’t we have isomers of first three members of alkane series?
Ans. (a) Those compounds, which have same molecular formula but different structural formulae, are called isomers.

(b) Isomerism is not possible in the first 3 alkanes primarily because branching is not possible from the first or the last carbon atom of the structure.

10. Shivani tried to cross a homozygous purple flower variety of pea plant (PP) with white flower variety of pea plant (pp). Mention the phenotype and genotype of the F₁ generation of offsprings. If the offsprings of the F₁generation are self bred. What will be the phenotypic and genotypic ratios of the F₂ generation ? State Mendel’s law of dominance.
Ans. In F₁ generation:
1. Phenotypes: All bear purple flower
2. Genotype: All are heterozygous dominant for purple flower i.e., Pp
In F₂ generation:
1. Phenotypic ratio: 3:1
2. Genotypic ratio: 1:2:1 1
Law of Dominance: Out of a pair of contrasting characters, only one is able to express while the other remains suppressed.

11. (a) What is Electric power? Express it in terms of potential difference V and resistance R.
(b) An electric iron of 1 kW is operated at 220 V. Find, which of the following fuses that respectively rated at 1 A, 3 A and 5 A can be used in it?
Ans. (a) Electric power: It is the rate of doing work by an energy source or the rate at which the electrical energy is dissipated or consumed per unit time in the electric circuit.

To run electric iron of 1 kW, rated fuse of 5 A should be used.

12. The figure below shows three cylindrical copper conductors along with their face areas and lengths. Compare the resistance and the resistivity of the three conductors. Justify your answer.

Calculate the readings of the ammeter and the voltmeter when key ‘K’ is closed. Give reason to justify your answer.
Ans.

Detailed :
For the figure a,
Length of the cylinder = L
Cross sectional area of the cylinder = A
Now we will simply put these values in the formula to find out resistance.
So, we get, R_a = ρ L / A
For the figure (b),
Length of the cylinder = 3L
Cross sectional area of the cylinder = A / 3
Now we will simply put these values in the formula to find out resistance.
So, we get R_b = ρ3L / (A / 3)
We can rewrite this equation as
R_b =ρ 9L / A
For figure (c),
Length of the cylinder = L / 3
Cross sectional area of the cylinder = 3A
Now, we will simply put these values in the formula to find out resistance.

Therefore, we can arrange the resistances in
the following order R_b > R_a > R_c
Since all conductors are made by copper
(same material), so their resistivity will remain
same i.e., ρ_a = ρ_b = ρ_c

13. Management of waste is very important in today’s society. The generation of waste is getting doubled day by day, as the population is increasing continuously. Moreover, the increase in waste is affecting the lives of many people.
(a) Differentiate between biodegradable and non-biodegradable substances with the help of one example each.
(b) List two changes in habit that people must adopt to dispose non-biodegradable waste, for saving the environment.
Ans. (a) Differences between biodegradable and non-biodegradable substances:

(b) Two methods of disposal of nonboiodegradable waste are:
(i) Recycling: The wastes are treated and same value materials are extracted for reuse.
(ii) Incineration: Medical and toxic waste are burnt at high temperature in Incinerators. Incinerators transform the waste into ashes.

Section – C

14. A blue colour flower plant denoted by BB is cross bred with that of white colour flower plant denoted by bb.
(a) State the colour of flower you would expect in their F₁ generation plants.
(b) What must be the percentage of white flower plants in F₂ generation if flowers of F₁ plants are self-pollinated? State the expected ratio of the genotypes BB and Bb in the F₂ progeny.
(c) State the type of plants which are not found in F1 generation but reappeared in F₂ generation. Write the reason for the same.
Ans. (a) The colour of all the flowers in F₁generation will be blue. 1
(b) Percentage of white flower plants in F₂ generation will be 25. The ratio of genotype BB and Bb in F₂ progeny will be 1:2. +
(c) White flower.
Reason: Being a recessive trait, white flower can only be expressed in the recessive homozygous condition or in the absence of dominant trait.

How dominant and recessive traits are different from each other?
Ans. Dominant trait: The character which gets expressed in the presence of its contrasting form is termed as dominant trait.
Recessive Trait: The trait which remains unexpressed in the presence of its contrasting form is called recessive trait.

15. Sanjana placed a current carrying long straight conductor PQ perpendicular to the plane of the paper as shown in the figure below. R and S are the two points at distance r₁and r₂ from it. Based on the given diagram, answer the questions given below:

(a) Find the directions of the magnetic fields produced by it at points R and S?
(b) Given r₁ > r₂, where will the strength of the magnetic field be larger? Give reasons.
(c) If the polarity of the battery connected to the wire is reversed, how would the direction of the magnetic field is changed? Give reason.
Ans. 15. (a) The magnetic field lines produced will be in anti-clockwise direction on the plane of the paper.
(b) Field at S > Field at R. Magnetic field strength for a straight current carrying conductor is inversely proportional to the distance from the wire.
(c) The current will be going from top to bottom in the wire and the magnetic field lines are now in the clockwise direction on the plane of the paper.

Explain the rule that is used to find the direction of the magnetic field for a straight current carrying conductor.
Ans. Right hand thumb rule: The thumb is aligned to the direction of the current and the direction in which the fingers are wrapped around the wire will give the direction of the
magnetic field.