Science Delhi Set 1 2023-2024 English Medium Class 10 Question Paper Solution

When 2 mL of sodium hydroxide solution is added to few pieces of granulated zinc in a test tube and then warmed, the reaction that occurs can be written in the form of a balanced chemical equation as:

\[\ce{NaOH + Zn -> NaZnO2 + H2O}\]

\[\ce{2NaOH + Zn -> Na2ZnO2 + H2}\]

\[\ce{2NaOH + Zn -> NaZnO2 + H2}\]

\[\ce{2NaOH + Zn -> Na2ZnO2 + H2O}\]

Select from the following a decomposition reaction in which source of energy for decomposition is light:

\[\ce{2FeSO4 -> Fe2O3 + SO2 + SO3}\]

\[\ce{2H2O -> 2H2 + O2}\]

\[\ce{2AgBr -> 2Ag + Br2}\]

\[\ce{CaCO3 -> CaO + CO2}\]

A metal and a non-metal that exists in liquid state at the room temperature are respectively:

Bromine and Mercury

Mercury and Iodine

Mercury and Bromine

Iodine and Mercury

Carbon compounds:

1. are good conductors of electricity.
2. are bad conductors of electricity.
3. have strong forces of attraction between their molecules.
4. have weak forces of attraction between their molecules.

The correct statements are:

i and ii

ii and iii

ii and iv

i and iii

Consider the following compounds:

\[\ce{FeSO4 ; CuSO4 ; CaSO4; Na2CO3}\]

The compound having maximum number of water of crystallisation in its crystalline form in one molecule is ______.

\[\ce{FeSO4}\]

\[\ce{CuSO4}\]

\[\ce{CaSO4}\]

\[\ce{Na2CO3}\]

Oxides of aluminium and zinc are ______.

acidic

basic

amphoteric

neutral

\[\ce{MnO2 + 4HCl -> MnCl2 + 2H2O + Cl2}\]

The reaction given above is a redox reaction because in this case ______.

\[\ce{MnO2}\] is oxidised and \[\ce{HCl}\] is reduced.

\[\ce{HCl}\] is oxidised.

\[\ce{MnO2}\] is reduced.

\[\ce{MnO2}\] is reduced and \[\ce{HCl}\] is oxidised.

1. The sex of a child is determined by what it inherits from the mother.
2. The sex of a child is determined by what it inherits from the father.
3. The probability of having a male child is more than that of a female child.
4. The sex of a child is determined at the time of fertilisation when male and female gametes fuse to form a zygote.

The correct statements are ______.

i and iii

ii and iv

iii and iv

i, iii and iv

Chromosomes:

1. carry hereditary information from parents to the next generation.
2. are thread like structures located inside the nucleus of an animal cell.
3. always exist in pairs in human reproductive cells.
4. are involved in the process of cell division.

The correct statements are:

i and ii

iii and iv

i, ii and iv

i and iv

In a nerve cell, the site where the electrical impulse is converted into a chemical signal is known as ______.

Axon

Dendrites

Neuromuscular junction

Cell body

A stomata closes when:

1. it needs carbon dioxide for photosynthesis.
2. it does not need carbon dioxide for photosynthesis.
3. water flows out of the guard cells.
4. water flows into the guard cells.

The correct reason(s) in this process is/are ______.

i only

i and iii

ii and iii

ii and iv

At what distance from a convex lens should an object be placed to get an image of the same size as that of the object on a screen?

Beyond twice the focal length of the lens.

At the principal focus of the lens.

At twice the focal length of the lens.

Between the optical centre of the lens and its principal focus.

The lens system of the human eye forms an image on a light sensitive screen, which is called as ______.

Cornea

Ciliary muscles

Optic nerves

Retina

The pattern of the magnetic field produced inside a current carrying solenoid is:

Identify the food chain in which the organisms of the second trophic level are missing.

Grass, goat, lion

Zooplankton, phytoplankton, small fish, large fish

Tiger, grass, snake, frog

Grasshopper, grass, snake, frog, eagle

In which of the following organisms, multiple fission is a means of asexual reproduction?

Yeast

Leishmania

Paramoecium

Plasmodium

Assertion (A): Hydrogen gas is not evolved when zinc reacts with nitric acid.

Reason (R): Nitric acid oxidises the hydrogen gas produced to water and itself gets reduced.

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

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

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

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

Assertion (A): Accumulation of harmful chemicals is maximum in the organisms at the highest trophic level of a food chain.

Reason (R): Harmful chemicals are sprayed on the crops to protect them from diseases and pests.

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

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

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

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

Assertion (A): The rate of breathing in aquatic organisms is much faster than in terrestrial organisms.

Reason (R): The amount of oxygen dissolved in water is very high as compared to the amount of oxygen in air.

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

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

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

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

Assertion (A): The rainbow is a natural spectrum of sunlight in the sky.

Reason (R): Rainbow is formed in the sky when the sun is overhead and water droplets are also present in air.

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

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

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

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

Name the type of chemical reaction in which calcium oxide reacts with water. Justify your answer by giving balanced chemical equation for the chemical reaction. 

What is the role of the acid in our stomach?

State one role of the following in human digestive system:

Villi

State one role of the following in human digestive system:

Anal Sphincter

State one role of the following in human digestive system:

Lipase

How is the movement of leaves of a sensitive plant different from the downward movement of the roots?

There is a hormone which regulates carbohydrate, protein and fat metabolism in our body. Name the hormone and the gland which secretes it. Why is it important for us to have iodised salt in our diet?

An object is placed at a distance of 10 cm from a convex mirror of focal length 15 cm. Find the position and nature of the image.

Show how you would connect three resistors each of resistance 6 Ω, so that the combination has a resistance of 9 Ω. Also justify your answer.

In the given circuit calculate the power consumed in watts in the resistor of 2 Ω : 2

Why don’t two magnetic lines of force intersect each other?

How is a uniform magnetic field in a given region represented ? Draw a diagram in support of your answer.

Write one chemical equation for the chemical reaction in which the following has taken place:

Change in colour

Mention colour change along with equation.

Write one chemical equation for the chemical reaction in which the following has taken place:

Change in temperature

Mention temperature change (rise/fall) along with equation.

Write one chemical equation for the chemical reaction in which the following has taken place:

Formation of precipitate

Mention compound precipitated along with equation.

The pH of a sample of tomato juice is 4.6. How is this juice likely to be in taste? Give reason to justify your answer.

How do we differentiate between a strong acid and a weak base in terms of ion-formation in aqueous solutions?

The acid rain can make the survival of aquatic animals difficult. How?

Why is respiratory pigment needed in multicellular organisms with large body size?

Give reason for the following:

Rings of cartilage are present in the throat.

Explain why, when air is taken in and let out during breathing, the lungs always contain a residual volume of air.

Give reasons for the following:

The diaphragm flattens and ribs are lifted up when we breathe in.

Give reasons for the following:

Walls of alveoli contain an extensive network of blood vessels.

Define the following:

Reflex action

With the help of a flow chart, show the path of a reflex action such as sneezing.

Study the diagram given below and answer the questions that follow:

1. Name the defect of vision represented in the diagram. Give reason for your answer.
2. List two causes of this defect.
3. With the help of a diagram show how this defect of vision is corrected.

State the rule to determine the direction of a magnetic field produced around a straight conductor-carrying current.

Name and state the rule of determine the direction of force experienced by a current carrying straight conductor placed in a uniform magnetic field which is perpendicular to it. 

Plants → Deer → Lion

In the given food chain, what will be the impact of removing all the organisms of second trophic level on the first and third trophic level? Will the impact be the same for the organisms of the third trophic level in the above food chain if they were present in a food web? Justify.

A gas 'X' which is a deadly poison is found at the higher levels of atmosphere and performs an essential function.

Name the gas and write the function performed by this gas in the atmosphere. Which chemical is linked to the decrease in the level of this gas? What measures have been taken by an international organisation to check the depletion of the layer containing this gas?

Define a homologous series of carbon compounds.

Why is the melting and boiling points of \[\ce{C4H8}\] higher than that of \[\ce{C3H6}\] or \[\ce{C2H4}\]?

Why do we NOT see any gradation in chemical properties of a homologous series compounds?

Write the name and structure of aldehyde with molecular form \[\ce{C3H6O}\].

Write the name and structures of ketone with molecular form \[\ce{C3H6O}\].

Write the name and structure of an organic compound 'X' having two carbon atoms in its molecule and its name is suffixed with '-ol'.

What happens when 'X' is heated with excess concentrated sulphuric acid at 443 K? Write chemical equation for the reaction stating the conditions for the reaction. Also, state the role played by concentrated sulphuric acid in the reaction.

Name and draw the electron dot structure of hydrocarbon produced in the above reaction.

Name three techniques/devices used by human females to avoid pregnancy. Mention the side effects caused by each.

What will happen if in a human female fertilisation takes place?

What will happen if in a human female an egg is not fertilised?

Draw a diagram showing spore formation in Rhizopus and label the (a) reproductive and (b) non-reproductive parts. Why does Rhizopus not multiply on a dry slice of bread?

Name and explain the process by which reproduction takes place in Hydra.

Define Electric power

Express electric power in terms of potential difference (V) and resistance (R).

An electric oven is designed to work on the mains voltage of 220 V. This oven consumes 11 units of electrical energy in 5 hours. Calculate:

1. power rating of the oven
2. current drawn by the oven
3. resistance of the oven when it is red hot

Write the relation between resistance R and electrical resistivity (ρ) of the material of a conductor in the shape of cylinder of length I and area of cross-section (a). Hence, derive the SI unit of electrical resistivity.

The resistance of a metal wire of length 3 m is 60 Ω. If the area of cross-section of the wire is 4 x 10⁻² m², calculate the electrical resistivity of the wire.

State how would electrical resistivity be affected if the wire (of part 'ii') is stretched so that its length is doubled. Justify your answer.

1. What is the cathode and anode made of in the refining of copper by this process? (1)
2. Name the solution used in the above process and write its formula. (1)
3.    
   1. How copper gets refined when electric current is passed in the electrolytic cell? (2)
      OR
   2. You have two beakers 'A' and 'B' containing copper sulphate solution. What would you observe after about 2 hours if you dip a strip of zinc in beaker 'X and a strip of silver in beaker 'B'? Give reason for your observations in each case. (2)

1. When Mendel crossed pea plants with pure tall and pure short characteristics to produce F₁ progeny, which two observations were made by him in F₁ plants?       1
2. Write one difference between dominant and recessive trail.       1
3. 1. In a cross with two pairs of contrasting characters
      

      RRYY	×	rryy
      (Round Yellow)		(Wrinkled Green)

      Mendel observed 4 types of combinations in F₂ generation. By which method did he obtain F₂ generation? Write the ratio of the parental combinations obtained and what conclusions were drawn from this experiment?         2
      OR
   2. Justify the statement:
      "It is possible that a trait is inherited but may not be expressed."         2

Study the data given below showing the focal length of three concave mirrors A, B and C and the respective distances of objects placed in front of the mirrors:

1. In which one of the above cases the mirror will form a diminished image of the object? Justify your answer.     1
2. List two properties of the image formed in case 2.     1
3.   
   1. What is the nature and size of the image formed by mirror C ? Draw ray diagram to justify your answer.     2
      OR
   2. An object is placed at a distance of 18 cm from the pole of a concave mirror of focal length 12 cm. Find the position of the image formed in this case.     2