Science Delhi set 3 2024-2025 English Medium Class 10 Question Paper Solution

Which one of the following gets biomagnified at different levels in a food chain?

Carbon monoxide

CFC’s

DDT

Manure

In the food chains given below. Select the most efficient food chain in terms of energy:

Grass → Grasshopper → Frog → Snake

Plants → Deer → Lion

Plants → Man

Phytoplankton → Zooplankton → Small Fish → Big Fish

An element ‘M’ has 25% of the electrons filled in the third shell as in the second shell. The element ‘M’ is ______.

Sodium

Magnesium

Aluminium

Calcium

An optical device ‘X’ is placed obliquely in the path of a narrow parallel beam of light. If the emergent beam gets displaced laterally, the device ‘X’ is ______.

plane mirror

convex mirror

glass slab

glass prism

A piece of wire of resistance ‘R’ is cut lengthwise into three identical parts. These parts are then connected in parallel. If the equivalent resistance of this combination is R', then the value of `R/(R')` is ______.

`1/9`

`1/3`

3

9

In which one of the following situations a chemical reaction does not occur?

Milk is left open at room temperature during summer.

Grapes get fermented.

An iron nail is left exposed to humid atmosphere.

Melting on glaciers.

In order to prepare dry hydrogen chloride gas in a humid atmosphere, the gas produced is passed through a guard tube (drying tube) which contains ______.

Calcium chloride

Calcium oxide

Calcium hydroxide

Calcium carbonate

Select from the following a hydrocarbon having one C-C bond and one C≡C bond:

Benzene

Cyclohexane

Butyne

Propyne

The essential element taken up from the soil by the plants to synthesize proteins is ______.

Phosphorus

Nitrogen

Iron

Magnesium

The minimum number of identical bulbs of rating 4 V, 6 W that can work safely with desired brightness when connected in series with a 240 V mains supply is ______.

20

40

60

80

An electric bulb is rated 220 V; 11 W. The resistance of its filament when it glows with a power supply of 220 V is ______.

4400 Ω

440 Ω

400 Ω

20 Ω

Select true statements about lymph from the following:

1. Lymph vessels carry lymph through the body and finally open into larger arteries.
2. Lymph contains some amount of plasma, proteins and blood cells.
3. Lymph contains some amount of plasma, proteins and red blood cells.
4. Lymph vessels carry lymph through the body and finally open into larger veins.

The true statements are:

A and B

B and D

A and C

C and D

Plants like rose and banana have lost the capacity to produce ______.

flowers

buds

seeds

fruits

When a pure-tall pea plant is crossed with a pure-dwarf pea plant, the percentage of tall pea plants in F₁ and F₂ generation pea plants will be, respectively, ______.

100%; 25%

100%; 50%

100%; 75%

100%; 100%

In a bisexual flower the male gametes are present in the ______.

anther

ovary

stigma

filament

To get an image of magnification −1 on a screen using a lens of focal length 20 cm, the object distance must be ______.

Less than 20 cm

30 cm

40 cm

80 cm

Assertion (A): In reptiles, the temperature at which the fertilized eggs are kept decides the sex of the offsprings.

Reason (R): Sex is not genetically determined in some animals.

Both Assertion (A) and Reason (R) are true, and Reason (R) is the correct explanation of Assertion (A).

Both Assertion (A) and Reason (R) are true, and Reason (R) is not the correct explanation of Assertion (A).

Assertion (A) is true, but Reason (R) is false.

Assertion (A) is false, but Reason (R) is true.

Assertion (A): In large animals, oxygen can reach different parts of the animal’s body easily.

Reason (R): Respiratory pigments take up oxygen from the air and carry it to body tissues.

Both Assertion (A) and Reason (R) are true, and Reason (R) is the correct explanation of Assertion (A).

Both Assertion (A) and Reason (R) are true, and Reason (R) is not the correct explanation of Assertion (A).

Assertion (A) is true, but Reason (R) is false.

Assertion (A) is false, but Reason (R) is true.

Assertion (A): Concentrated nitric acid is diluted by adding water slowly to acid with constant stirring.

Reason (R): Concentrated nitric acid is easily soluble in water.

Both Assertion (A) and Reason (R) are true, and Reason (R) is the correct explanation of Assertion (A).

Both Assertion (A) and Reason (R) are true, and Reason (R) is not the correct explanation of Assertion (A).

Assertion (A) is true, but Reason (R) is false.

Assertion (A) is false, but Reason (R) is true.

Assertion (A): White light is dispersed by a glass prism into seven colours.

Reason (R): The red light bends the least while the violet the most when a beam of white light passes through a glass prism.

Both, Assertion (A) and Reason (R) are true, and Reason (R) is the correct explanation of Assertion (A).

Both, Assertion (A) and Reason (R) are true, and Reason (R) is not the correct explanation of Assertion (A).

Assertion (A) is true, but Reason (R) is false.

Assertion (A) is false, but Reason (R) is true.

Name the compound used in black and white photography. State whether the reaction that occurs is exothermic or endothermic. Give justification for your answer.

Show the formation of calcium chloride by the transfer of electrons from one element to the other. Atomic Number of calcium and chlorine is 20 and 17 respectively.

“Aluminium oxide is an amphoteric oxide.” Justify this statement giving chemical equation for the reactions involved.

Name the tissues which form the vascular bundle. State their function in plants.

Draw a ray diagram to show the refraction of a ray of light passing through an equilateral glass prism. Mark the angle through which the emergent ray bends from the direction of the incident ray and also name it.

Name the type of lenses used for the correction of presbyopia defect.

Write the structure of the lenses commonly used for the correction of presbyopia defect giving reason for such designs.

Explain with the help of a flow chart that in human beings the father is responsible for the sex (male or female) of the child.

Draw the pattern of magnetic field lines due to a current carrying straight conductor. Mark on it the direction of current in the conductor and the direction of the magnetic field developed. Name the rule that helps us to determine the direction of magnetic field lines in this case.

If we want to obtain a virtual and magnified image of an object by using a concave mirror of focal length 18 cm, where should the object be placed? Use the mirror formula to determine the object distance for an image of magnification +2 produced by this mirror to justify your answer.

Name and describe the most widely used method for refining impure metals?

What is the first step of cellular respiration?

In which part of the cell does cellular respiration occur?

Write the equation for the process of breakdown of glucose in a human cell in the presence of oxygen.

Write the equation for the process of breakdown of glucose in a human cell due to lack of oxygen.

Why do we need to balance chemical equations?

Name and state the law that suggests the balancing of a chemical equation.

Balance the following chemical equation:

\[\ce{Zn + H3PO4 -> Zn3(PO4)2 + H2}\]

Define precipitation reaction.

Give an example of a precipitation reaction and also express the reaction that occurs in the form of a balanced chemical equation.

What are decomposers?

Give two examples of decomposers.

State how decomposers maintain a balance in an ecosystem.

Define the term “potential difference” between two points in an electric circuit carrying current.

Name and define the S.I. unit of “potential difference” between two points in an electric circuit carrying current. Also express it in terms of the S.I. unit of work and charge.

State two limitations of electrical impulses in multicellular organisms.

Why is chemical communication better than electrical impulses as a means of communication between cells in a multicellular organism?

Draw the pattern of the magnetic field lines for the two parallel straight conductors carrying current of the same magnitude ‘I’ in opposite directions, as shown. Show the direction of the magnetic field at a point O, which is equidistant from the two conductors. (Consider that the conductors are inserted normal to the plane of a rectangular cardboard.)

In our houses we receive A.C. electric power of 220 V. In electric iron or electric heater cables having three wires with insulation of three different colours - red, black and green are used to draw current from the mains.

1. What are these three different wires called? Name them colourwise.
2. What is the potential difference between the red wire and the black wire?
3. What is the role of the wire with green insulation in case of accidental leakage of electric current to the metallic body of an electrical appliance?

By using the given experimental set-up. How can it be shown that:

1. a force is exerted on the current-carrying conductor AB when it is placed in a magnetic field.
2. the direction of force can be reversed in two ways.

When will the magnitude of the force be highest?

State Fleming’s left-hand rule.

Name the parts marked as ‘A’ and ‘B’ in the given diagram. Write in detail the changes that take place in a flower when the product of ‘B’ reaches ‘A’ till a fruit is formed.

In the human female reproductive system, state the changes that take place once fertilisation has taken place. Write the role of the placenta in this process.

What happens when the egg is not fertilised?

A carbon compound ‘A’ on heating with excess conc. H₂SO₄, forms a compound ‘B’, which on addition of one mole of hydrogen gas in the presence of nickel catalyst forms a compound ‘C’. ‘C’ on combustion in air forms 2 moles of carbon dioxide and 3 moles of water. Identify ‘A’, ‘B’ and ‘C’ and write their structures. Give chemical equations of the reactions involved. Also state the role of concentrated sulphuric acid in the formation of ‘B’ from ‘A’.

A carbon compound ‘A’ is widely used as a preservative in pickles and has a molecular formula of C₂H₄O₂. This compound reacts with ethanol to form a sweet smelling compound ‘B’.

1. Identify the compound ‘A’ and write its structure.
2. Write the chemical equation for the reaction of ‘A’ with ethanol to form compound ‘B’. State the role of the presence of an acid in the reaction.
3. How can we get compound ‘A’ back from ‘B’?
4. How can ‘A’ be obtained from ethanol?
5. Name the gas produced when compound ‘A’ reacts with washing soda.

1. Give any one more instance in which this type of spectrum is observed.    (1)
2. What happens to white light in the above case?    (1)
3. 1. List two conditions necessary to observe a rainbow.   (2)
      OR
   2. Draw a ray diagram to show the formation of a rainbow. Mark on it points (a), (b) and (c) as given below:   (2)
      1. Where dispersion of light occurs.
      2. Where light gets reflected internally.
      3. Where final refraction occurs.

1. Name the acid and the base from which common salt can be obtained.    (1)
2. State the nature (acidic/basic/neutral) of sodium chloride. Give a reason for the justification for your answer.    (1)
3. 1. What happens when electric current is passed through an aqueous solution of sodium chloride (called brine)? Name the products obtained along with the corresponding places in the electrolytic cell where each of these products is obtained.    (2)
      OR
   2. How is washing soda obtained from sodium chloride? Give the chemical equation of the reactions involved in the process.    (2)

1. Name the action by which we protect ourself in the situation mentioned above and define it.    (1)
2. Write the role of (a) motor and (b) relay neuron.   (1)
3. 1. What are the two types of nervous systems in the human body? Name the components of each of them.    (2)
      OR
   2. Which part of the human brain is responsible for:   (2)
      1. thinking
      2. picking up a pencil
      3. controlling blood pressure
      4. controlling hunger