Science Delhi set 2 2024-2025 English Medium Class 10 Question Paper Solution

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

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%

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

flowers

buds

seeds

fruits

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.

The property by virtue of which a solid material can be drawn into thin wires is called ______.

malleability

ductility

rigidity

resistivity

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

Which one of the following has half the number of chromosomes and half the amount of DNA as compared to the non-reproductive body cells?

Male germ cell

Female grm cell

Zygote

Both, male and female germ cells

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

Phosphorus

Nitrogen

Iron

Magnesium

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

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 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

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

Assertion (A): All exothermic reactions are accompanied with evolution of heat and light.

Reason (R): Combination reactions may or may not be exothermic.

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): When ciliary muscles contract, eye lens becomes thin.

Reason (R): Ciliary muscles control the power of the eye lens.

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): 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.

While burning a magnesium ribbon in air, list two safety measures which should be followed.

What do you observe when Magnesium ribbon is burnt in oxygen.

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.

“In human alimentary canal the small intestine is designed to absorb the digested food.” Justify this statement.

Pure-tall (TT) pea plants are crossed with pure-dwarf (tt) pea plants. The pea plants obtained in F₁ generation are then self pollinated to produce F₂ generation.

1. What do the plants of F₁ generation look-like? Justify your answer.
2. What is the ratio of pure-tall plants to pure-dwarf plants in F₂ generation?

Show the formation of magnesium chloride by electron transfer. Write the name of the cation and anion present in the compound formed. (Atomic Number of Mg = 12, Cl = 17)

How is zinc extracted from its ore? Name the processes involved in the extraction and write chemical equations for the reactions that occur during these processes.

State the role of an electric fuse, used in series with an electrical appliance.

Why should in an electric circuit a fuse with defined rating not be replaced by one with a larger rating?

What are decomposers?

Give two examples of decomposers.

State how decomposers maintain a balance in an ecosystem.

Samples of four metals A, B, C and D were added one by one to the following solutions. The results obtained were tabulated as follows:

Use the table above to answer the following questions about metals A, B, C and D:

1. Which is the least reactive metal?
2. What would be observed if C is added to a solution of copper sulphate?
3. Arrange the metals A, B, C and D in the order of their decreasing reactivity.

1. Study the diagram and name the parts marked as A, B, C and D.
2. Write the function of A and C.

The electrical resistivity of three materials A, B and C at 20°C is given below:

1. Classify these materials as conductor, alloy and insulator.
2. Give one example of each of these materials and state one use of each material in the design of an electrical appliance say an electric stove or an electric iron.

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

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.

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?

What are structural isomers?

Draw two structural isomers of butane.

Give reason why propane has no structural isomers?

What happens when magnesium is burnt in air.

Differentiate between the flames obtained when butane and butyne both are burnt in air in the similar conditions.

State the reason why carbon can neither form C⁴⁺ cations nor C⁴⁻ anions but forms covalent compound.

What is meant by a functional group in carbon compounds?

Write in tabular form the structural formula and the functional group present in the following compound:

Ethanol

Write in tabular form the structural formula and the functional group present in the following compound:

Ethanoic acid

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.

What is Regeneration?

Give one example of an organism that shows a regeneration process.

Give one example of an organism that does not show a regeneration process.

Why does regeneration not occur in the latter?

Water in a pond appears dark green and contains filamentous structures. Name these structures and the method by which they reproduce. Explain the process.

Name the part performing the following function in the human male reproductive system:

Carries sperm

Name the part performing the following function in the human male reproductive system:

Production of male gametes.

Name the part performing the following function in the human male reproductive system:

Whose secretion makes the transport of sperms easier.

Name the part performing the following function in the human male reproductive system:

Provide suitable temperature for sperm formation.

Write any two characteristics of sperm.

What are surgical contraceptive methods?

Give the side effects caused by the surgical contraceptive procedure.

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