List of top Questions asked in CBSE Compartment X- 2023

Define water of crystallisation.
Define trophic levels. At which trophic level do we find (i) secondary and (ii) tertiary consumers in a food chain? What will happen if all the organisms of a trophic level die? Give reasons to justify your answer.
With the help of a labelled circuit diagram, illustrate the pattern of the magnetic field lines of the magnetic field produced around a straight current carrying conductor. Explain how, with the help of right-hand thumb rule, we can determine and mark the direction of magnetic field lines due to a current.
What is Tyndall effect? Give two examples where this phenomenon is observed. Give reason to explain this phenomenon.
Write any two ways by which plants obtain carbon dioxide. What causes the opening and closing of the stomata?
What is meant by residual volume of air in the lungs?
Give the structure and function of alveoli in human respiratory system.
Why are carbon compounds exceptionally stable?
An organic compound ‘X’ when reacts with sodium liberates hydrogen. The same compound ‘X’ when heated at 443 K in the presence of concentrated sulphuric acid gives an unsaturated hydrocarbon.
(i) Identify ‘X’.
What is photosynthesis? Name the organelle and the organs in which photosynthesis takes place. Where does the oxygen liberated come from during this process? What happens to the carbohydrates which are not immediately used by the plant?
List any two methods by which the solid wastes generated in urban areas can be safely disposed off.
State any one advantage of using cloth bags over plastic bags.
What will happen if an electric oven of rating 3 kW; 220 V is operated in a domestic electric circuit (220 V) that has a current rating of 10 A? Give reason to justify your answer.

Draw a labelled ray diagram for the image formation by a concave mirror when an object is placed between its centre of curvature and focus.

Find the magnification of the image formed by a spherical mirror from the following data :
$u = -20$ cm,  $f = -15$ cm.

“In human beings, the sex of a newborn child depends on the father and not the mother.” Justify this statement with the help of a flow diagram.
Name the glands which add their secretions to the sperms. List two functions of these secretions.
Are these compounds soluble in organic solvents such as kerosene or petrol? Justify your answer.
When two compounds namely sodium chloride and calcium chloride are heated directly, one by one on the flame of a burner, they impart different colours to the flame.
Name the colour imparted by (1) sodium chloride and (2) calcium chloride.
Assertion (A) : A rainbow is an artificial spectrum of white light appearing in the sky after a rain shower.
Reason (R) : The water droplets act like small prisms.
Assertion (A) : Each human trait is influenced by both paternal and maternal DNA.
Reason (R) : As compared to the father, the mother contributes more amount of genetic material to the child.
Assertion (A) : A hormone called abscisic acid inhibits growth in plants.
Reason (R) : The role of auxins is opposite to that of abscisic acid in plants.
The shape of magnetic field lines produced (i) inside a solenoid (ii) around a straight conductor, both carrying current of the same magnitude are, respectively :

The resistance of a wire does not depend on its :

A material used for making heating elements of electrical heating devices should have :