List of top Questions asked in CBSE Class X

During respiration, exchange of gases occurs in:
In a nerve cell (neuron), the conversion of electrical signal to chemical signal occurs in/at:
The part of a seed that stores food, the future root, and the future shoot respectively are:
Two pea plants, one round green (\(RRyy\)) seeds and another with wrinkled yellow (\(rrYY\)) seeds produce \(F_1\) progeny that has round yellow (\(RrYy\)) seeds. If the \(F_1\) progeny plants are selfed, then the minimum number of plants of the \(F_2\) progeny will have the following observable characters:
Consider the following groups:
  1. Cotton, silk, nylon, leather
  2. Wool, wood, soap, wheat
  3. Banana, cat, rat, tree
  4. Soap, detergent, silk, polyester
The groups of biodegradable material are:
two statements are given — one labelled as Assertion (A) and the other labelled as Reason (R). Select the correct answer to these questions from the codes (A), (B), (C) and (D) as given below.
Assertion (A): The intensity of the magnetic field produced at the centre of a current-carrying circular coil increases on increasing the number of turns in the coil.
Reason (R): The current that flows in each turn of the coil has the same magnitude and same direction, and the magnetic field, due to each turn, just adds up.
two statements are given — one labelled as Assertion (A) and the other labelled as Reason (R). Select the correct answer to these questions from the codes (A), (B), (C) and (D) as given below.
Assertion (A): Silver oxide (\(\text{Ag}_2\text{O}\)) is an amphoteric oxide.
Reason (R): Metal oxides which react with both acids as well as bases are called amphoteric oxides.
two statements are given — one labelled as Assertion (A) and the other labelled as Reason (R). Select the correct answer to these questions from the codes (A), (B), (C) and (D) as given below.
Assertion (A): Chromosomes inherited from the parents decide the sex of a child.
Reason (R): Y chromosome in a male child is inherited from the father.
two statements are given — one labelled as Assertion (A) and the other labelled as Reason (R). Select the correct answer to these questions from the codes (A), (B), (C) and (D) as given below.
Assertion (A): Greater numbers of individuals are present in lower trophic levels of all food chains.
Reason (R): As the amount of energy decreases at each successive trophic level, larger numbers of individuals are required at the lower trophic levels to support higher/next trophic levels.
List four properties of the images formed by a plane mirror.
Write the definitions of the following terms in the context of a concave mirror:
  1. Pole
  2. Centre of curvature
  3. Radius of curvature
  4. Principal axis
Write the shape of the magnetic field produced by a current carrying straight conductor. State the rule to find the direction of this field.
A compound ‘X’ on heating at \(373 \, \text{K}\) loses water molecules and becomes ‘Y’. Substance ‘Y’ is used by doctors for supporting fractured bones in the right position.
  1. Identify ‘X’ and ‘Y’.
  2. How can we obtain ‘X’ from ‘Y’?
Two solutions X and Y give red and blue colour respectively with universal indicator.
  1. In which solution is the hydrogen ion concentration more than the other? Justify your answer.
  2. If X and Y are mixed in proper amounts and the resultant mixture is tested with a universal indicator, it turns green. What is the nature of the salt formed? Justify your answer.
When a strip of aluminium metal is dipped in a solution of ferrous sulphate, the pale green colour of the solution fades away. State the conclusion you can draw from this observation. Write the chemical equation for the reaction that occurs in this case.
Give reason for this: Rings of cartilage are present in the throat.
Name the part of the human brain which is responsible for the following actions:
  1. Thinking
  2. Blood pressure
  3. Maintaining posture and balance
  4. Salivation
Name the organ/part of a plant which shows:
  1. Positive hydrotropism
  2. Positive phototropism
  3. Negative geotropism
  4. Positive chemotropism
How does an electric fuse prevent the circuit and the appliances from possible damage due to short circuiting or overloading?
How is the type of current used in household supply different from the one given by dry cells or storage batteries?
For distant transmission of electric power, an alternating current (ac) is considered to be advantageous over direct current (dc). Why?
A straight conductor is suspended horizontally with its axis perpendicular to the magnetic field of a strong horseshoe magnet. The conductor gets displaced towards the right when a steady current is passed through it. What will happen to the displacement of the conductor if:
  1. Polarity of the horseshoe magnet is reversed?
  2. Direction of current in the conductor is reversed?
  3. Current through the conductor is increased?
Name and state the rule for determining the direction of force on a current carrying conductor placed in a magnetic field.
When and where does a rainbow appear in the sky? List the phenomena of light in proper sequence which occurs during the formation of a rainbow. Why can a rainbow not be seen from the surface of the moon?
Name and explain the most widely used method for refining impure metals.