List of top Questions asked in CBSE Compartment X

M is a point on y-axis at a distance of 4 units from x-axis and it lies below the x-axis. The distance of point M from point Q(3, 1) is:

As shown in the diagram, an electron enters perpendicularly into a magnetic field. Using Fleming’s Left-Hand Rule, determine the direction of the force experienced by the electron. 

A person must hold reading material at a distance greater than 25 cm for clear vision.
(i) What is the name of this visual defect?
(ii) Draw a ray diagram to show its correction.
With the help of a labeled diagram, show the pattern of magnetic field lines around a current-carrying straight conductor. Explain how we can use the right-hand thumb rule to find the direction of magnetic field due to current.
Assertion (A): Both plants and animals exhibit chemical coordination.
Reason (R): Plant hormones regulate directional growth while in animals, hormones do not control directional growth.
Assertion (A): Soap does not form lather with hard water.
Reason (R): Hard water contains salts of calcium and magnesium which react with soap to form insoluble substances (scum).
What is meant by biomagnification?

Consider the following statements: 
Every step in a food chain is called a trophic level. 
Decomposers convert complex organic matter into simple substances that mix with the soil. 
In a food chain, energy increases from lower to higher trophic level.
Interlinking of multiple food chains forms a food web. 
Which of the above statements are correct?

In plants, waste products like resin and gum are stored in:
Select the hydrocarbon from the following which contains one C$\equiv$C triple bond and one C–C single bond:
The acid present in nettle leaves is:
A few drops of turmeric solution are added to a colorless liquid. If the liquid turns red in color, the liquid could be:
Write the name of the part of the human female reproductive system where the following functions take place:
Maturation of ovum
Fertilization of ovum with sperm
Zygote formation
What happens when:
The ovum is fertilized?
The ovum is not fertilized?
Explain each with an example:
(1) Unisexual flower
(2) Bisexual flower
Identify the labeled parts A, B, C, and D in the given diagram of a flower.
"Pollination can occur without fertilization, but fertilization cannot occur without pollination." Justify this statement.
Give one example each of (i) a natural ecosystem and (ii) an artificial (man-made) ecosystem.
A certain aqueous solution turns blue litmus red. On adding an excess of which of the following solutions will this change be reversed?
Lemon juice
Magnesium hydroxide
Vinegar
Calcium sulphate
Which of the following will turn phenolphthalein pink?
CH$_3$COOH
Ca(OH)$_2$
HCl
NaOH
Write the name and formula of a gas whose solution is basic.
Why is a basic solution used to treat a bee sting?
Name the acids present in:
Tomato
Tamarind (imli)
Define crystalline water.
(i) Why do the members of a homologous series show similar chemical properties?
(ii) What is the difference in number of carbon and hydrogen atoms between two consecutive members of a homologous series?
Give one example each of (i) Alkanes, (ii) Alcohols, (iii) Aldehydes.