CBSE Class 10 Science Term 2 Sample Paper
Class – X Exam 2021-22
Science (086)
Time Allowed: 120 minutes
(Maximum Marks: 40)
General Instructions:
All questions are compulsory.
- The question paper has three sections and 15 All questions are compulsory.
- 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 (04)
- Internal choices have been provided in some A student has to attempt only one of the alternatives in such questions.
Section A
1. Answer the following question :
1. Illustrate the following reactions with example :
-
- Substitution reaction
- Addition reaction
2. Inert gases are placed in a separate group in the modern periodic table :
-
- How many valence electrons do most of them have?
- Why are they unreactive ?
3. (a) What is vegetative propagation ?
(b) Write any two advantages of practising this method.
4. (a) Explain the terms :
- implantation,
- placenta
(b) What is the average duration of human pregnancy?
5. How does the process of budding differ from the process of spore formation?
OR
What are sexually transmitted diseases? Name an STD which damages the immune system of human body.
6. What is a compass needle ? What happens when a compass needle is placed :
-
- in a region having no magnetic field,
- near a bar magnet ?
OR
Identify the poles of the magnet in the given Figure (i) and (ii).
7. Consider the food chain :
What will happen it lions are removed from the above food chain ?
OR
What is depicted in the above mentioned scheme ?
Section B
8. Differentiate between the arrangement of elements in Mendeleev’s periodic table and Modern periodic table.
9. The electronic configuration of four elements A, B, C and D are given as follows: A–2, 8, B–2, 8, C–2, 8, 2, D–2, 8, 8.
- Which of them belong to the same period? Name the
- Which of them belong to the same group? Name the
OR
- How does atomic radius change as we move from left to right in a period ?
- The positions of three elements P,Q and R in the Periodic Table are shown below:
| Group 15 | Group 16 | Group 17 |
| ………. | ………. | ………. |
| ………. | ………. | Q |
| ………. | ………. | ………. |
| P | ………. | R |
Which one of the three elements is most non-metallic?
10. How did Mendel’s experiments show that different traits are inherited independently?
11. Calculate the total cost of running the following electrical devices in the month of September, if the rate of 1 unit of electricity is `600.
- Electric heater of 1000 W for 5 hours daily.
- Electric refrigerator of 400 W for 10 hours daily.
12. For the circuit diagram given below calculate :
-
- the value of current through each resistor.
- the total current in the circuit.
- the total effective resistance of the circuit.
OR
Why does a current carrying conductor kept in magnetic field experience force. On what factors does the direction of this force depend ? Name and state the rule used for determination of direction of this force.
13. (a) What are decomposers ?
(b) State in brief the role of decomposers in the environment.
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. Read the following case based passage and answer the questions given after passage.
A gene is the basic physical and functional unit of heredity genes are maple up of DNA.
Most of the characters or traits of an organism are controlled by the genes. Genes are actually segments of DNA guiding the formation of proteins by the cellular organelles. These proteins may be enzymes, hormones, antibodies, and structural components of different types of tissues. In other words, DNA/ genes are responsible for structure and functions of a living body. Genotype of an individual controls its phenotype.
Gene T
Gene t
” Responsible for synthesis of efficient enzyme (Proteins)
” Responsible for synthesis of less efficient enzyme
” More production of growth hormone
” Less production of growth hormone
” Result in Tall Plants
” Result in Short Plants
(i) Two pea plants one with round green seeds (RRyy) and another with wrinkled yellow (rrYY) seeds produce F1 progeny that have round, yellow (RrYy) seeds. When F1 plants are selfed, the F2 progeny will have new combination of characters. Choose the new combination from the following.
- Wrinkled, green
- Wrinkled, yellow
- Round, green
- Round, yellow
(a) I and II (b) I and IV
(c) II and III (d) I and III
(ii) A section of DNA providing information for one protein is called-
(a) Gene
(b) Nucleus
(c) Chromosomes
(d) Trait
(iii) Which one of the following is present in the nucleus?
(a) Chromosomes
(b) Gene
(c) DNA
(d) All of these
(iv) Select the statements that describe characteristics of genes
- In individuals of a given species, a specific gene is located on a particular chromosome
- A gene does not code for proteins
- Genes are specific sequence of bases in a DNA molecule
- Each chromosome has only one gene
(a) I and II (b) I and III
(c) I and IV (d) III and IV
(v) A Mendelian experiment consisted of breeding tall pea plants bearing violet flowers with short pea plants bearing white In the progeny, all bore violet flowers, but almost half of them were short. This suggests that the genetic makeup of tall plant can be depicted as
(a) TtWw (b) TTWW
(c) TTww (d) TtWW
15. Read the following case based passage and answer the questions given after passage.
In the series combination, the resistances are joined end to end. For a series combination of resistors, Rs = /Ri and current through each resistor is same but their potential difference between their ends are different according to their resistance. When two or more resistors are combined in such a way that their first ends are connected to one point and the second ends to another point. In a parallel combination of resistors and potential drop across each resistor is same but current in different resistances are different.
- If we connect n bulbs each with a rated power P in series, what is the total power consumed by combination at rated current?
- If we connect n bulbs each with a rated power P in parallel, what is the total power consumed by combination at rated voltage?
- The power consumed by n equal resistance in parallel is x times that of power consumed in series, if the voltage supply is Find the value of x .
OR
If resistors, 4 Ω, 5 Ω and 6 Ω are connected in series with 5V battery, calculate the total power consumed by the combination?