Top 10 questions in science cbse class 10 exam 2020

Top 10 Questions in Science CBSE Class 10 Exam - 2020

Check top 10 important science questions and answers that will help you plan your study and revision in CBSE Class 10 Science exam - 2020

By Topperlearning Expert 28th Feb, 2020 | 03:38 pm

The CBSE Class 10 Science paper is divided into five sections—A, B, C, D and E. Every section carries certain weightage and is a combination of compulsory and optional questions. These questions are also based on the guidelines set by NCERT and follow the CBSE blueprint. Here we present the important questions for CBSE Class 10 Science that must be revised before the exam. These questions are set by our academic experts and have been drafted based on their expertise and experience.

Important Questions & Answers CBSE Class 10 Board Exam 2020 : Science

1. (a) What are amphoteric oxides? Give two examples.

(b) How is aluminium metal extracted? Explain with the help of an equation.

Solution:

(a) Amphoteric oxides are those oxides which show properties of both acids as well as bases to form salts and water.

(b) Aluminium metal is extracted by the electrolytic reduction (electrolysis) of molten aluminium oxide. When electric current is passed through molten aluminium oxide, it decomposes to form aluminium metal and oxygen gas.

2. (a) What happens when a strip of lead metal is placed in a solution of copper chloride? Write the balanced chemical equation for the reaction along with the colour changes observed during the reaction.

(b) Draw the structures of possible isomers of butane, C₄H₁₀. Also, explain why we cannot have isomers of the first three members of the alkane series.

3. Select from the table below:

Group Nos.
IA	IIA	IIIA	IVA	VA	VIA	VIIA	0
1	2	13	14	15	16	17	18
Li		D			O	J	Ne
A	Mg	E	Si		H	K
B	C		F	G			L

Which is the most electronegative?
How many valence electrons are present in G?
Write the formula of the compound between B and H.
In the compound between F and J, what type of bond will be formed?
Draw the electron–dot structure for the compound formed between C and K.

4. What are the different ways in which glucose is oxidised to provide energy in various organisms?

5. Draw a neat and well-labelled diagram of the structure of the human brain. Mention the functions of the different parts of the human brain

6. (a) Write the function of the following parts in the human female reproductive system:

(i) Ovary (ii) Oviduct (iii) Uterus

(b) Describe in brief the structure and function of the placenta.

7. (a) ‘Sex of children is determined by what they inherit from the father and not from the mother.’ Justify.

(b) Explain the result of a monohybrid cross.

8. (a) Two lenses A and B have a power of +3 D and –4 D, respectively. What is the nature and focal length of each lens?

(b) A combination of lens contains two converging lens of focal length 30 cm and 50 cm and a diverging lens of focal length 40 cm. Find the power and focal length of the combination.

9. What is a magnetic field? List the characteristics of a magnetic field. If two magnetic field lines intersect at a point, what does that indicate?

10. An electric iron draws 2.4 amperes of current from a 240-V source.

Find

(a) Resistance of the electric iron

(b) Power consumed by the electric iron

For reviewing all the important answers and practice material for CBSE Class 10 Science exam 2020 click here:

CBSE Class 10 Science exam 2020 - Sample Papers

CBSE Class 10 Science exam 2020 - Previous years papers

CBSE Class 10 Science exam 2020 - Mock bo ard exam

CBSE Class 10 Science exam 2020 - Revision notes

CBSE Class 10 Science exam 2020 - Practice tests

CBSE Class 10 Science exam 2020 - Chapter notes

CBSE Class 10 Science exam 2020 - Webinar

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