Science Official 2023-2024 English Medium Class 10 Question Paper Solution

A chemical reaction in which exchange of ions occurs between the reactants is known as ______.

Endothermic reaction

Exothermic reaction

Double displacement reaction

Displacement reaction

A zygote is formed by the fusion of a male gamete and a female gamete. The number of chromosomes in the zygote of a human is ______.

23

44

46

92

The part of a seed which is a source of food during germination of seed is ______.

Cotyledon

Radicle

Plumule

Embryo

The plants that can be raised by the method of vegetative propagation are ______.

sugarcane, roses, grapes

sugarcane, mustard, potato

banana, orange, mustard

papaya, mustard, potato

A plant growth inhibitor hormone which causes wilting of leaves is ______.

Auxin

Cytokinin

Abscisic acid

Gibberellin

An aqueous solution of a salt turns blue litmus to red. The salt could be the one obtained by the reaction of ______.

HNO₃ and NaOH

H₂SO₄ and KOH

CH₃COOH and NaOH

HCl and NH₄OH

Four solutions, namely glucose, alcohol, hydrochloric acid and sulphuric acid filled in four separate beakers are connected one by one in an electric circuit with a bulb. The solutions in which the bulb will glow when current is passed are ______.

Glucose and alcohol

Alcohol and hydrochloric acid

Glucose and sulphuric acid

Hydrochloric acid and sulphuric acid

The metals which are found in both free state as well as combined state are ______.

Gold and platinum

Platinum and silver

Copper and silver

Gold and silver

The number of single and double bonds present in a molecule of benzene (C₆H₆) respectively, are ______.

6 and 6

9 and 3

3 and 9

3 and 3

In human beings, when the process of digestion is completed, the (i) proteins, (ii) carbohydrates and (iii) fats are respectively finally converted into ______.

(i) amino acids, (ii) glucose, (iii) fatty acids

(i) amino acids, (ii) glucose, (iii) fatty acids and glycerol

(i) glucose, (ii) fatty acids and glycerol, (iii) amino acids

(i) sugars, (ii) amino acids, (iii) fatty acids and glycerol

Some wastes are given below:

1. Garden waste
2. Ball point pen refills
3. Empty medicine bottles made of glass
4. Peels of fruits and vegetables
5. Old cotton shirt

The non-biodegradable wastes among these are ______.

(i) and (ii)

(ii) and (iii)

(i), (iv) and (v)

(i), (iii) and (iv)

A rectangular loop ABCD carrying a current I is situated near a straight conductor XY, such that the conductor is parallel to the side AB of the loop and is in the plane of the loop. If a steady current I is established in the conductor as shown, the conductor XY will ______.

remain stationary

move towards the side AB of the loop

move away from the side AB 

rotate about its axis

Absolute refractive indices of glass and water are `3/2 and 4/3` respectively. If the speed of light in glass is 2 × 10⁸ m/s, the speed of light in water is ______.

`9/4xx10^8` m/s

`5/2xx10^8` m/s

`7/3xx10^8` m/s

`16/9xx10^8` m/s

When a beam of white light passes through a region having very fine dust particles, the colour of light mainly scattered in that region is ______.

Red

Orange

Blue

Yellow

Consider the following combinations of resistors:

1. 
   
2. 
   
3. 
   
4. 
   
   The combinations having equivalent resistance 1 Q is/are ______.

I and IV

Only IV

I and II

I, II and III

An electric iron of resistance 20 Ω draws a current of 5 A. The heat developed in the iron in 30 seconds is ______.

15000 J

6000 J

1500 J

3000 J

Assertion (A): Oxygen is essential for all aerobic forms of life.

Reason (R): Free oxygen atoms combine with molecular oxygen to form ozone.

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, but 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): Most of the plants close their stomata at night.

Reason (R): Closing of stomata helps to conserve water as large amount of water evaporates from the leaves.

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, but 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): The extraction of metals from their sulphide ores cannot take place without roasting the ore.

Reason (R): Roasting converts sulphide ores directly into metals.

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, but 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): Magnetic field lines never intersect each other.

Reason (R): If they intersect, then at the point of intersection, the compass needle would point towards two directions, which is not possible.

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, but 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.

We need to water the soil in plants on a regular basis but it ultimately reaches the leaves of the plant. Explain how this takes place.

Name the type of nutrition exhibited by Amoeba. Explain how food is taken in and digested by this organism.

A spatula full of sodium carbonate is taken in a test tube and 2 mL of dilute ethanoic acid is added to it.

Write a chemical equation for the reaction.

A spatula full of sodium carbonate is taken in a test tube and 2 mL of dilute ethanoic acid is added to it.

Suggest a method of testing the gas liberated in the reaction.

1 gram of solid sodium chloride was taken in a clean and dry test tube and concentrated sulphuric acid was added to it.

1. Name the gas evolved in the reaction.
2. What will be observed when this gas is tested with (1) dry and (II) wet blue litmus paper?
   Write your conclusion about the nature (acidic/basic) of this gas.

Some metals react with acids to produce salt and hydrogen gas. Illustrate it with an example. How will you test the presence of this gas?

Mendel crossed pea plants with two pairs of contrasting characters.

He observed 4 types of combinations in F2 generation. Which of the combinations were new? Write the conclusion drawn by this experiment.

Name the phenomenon of light responsible for Tyndall effect. Write an event where this phenomenon can be observed.

Write Joule's law of heating.

How is Joule's law effect useful in electric circuits where fuse is used as a safety device?

A small amount of copper oxide was taken in a beaker and dilute hydrochloric acid was added with continuous stirring of the solution. Name the compound formed and state the colour of its solution. Write the balanced chemical equation for the reaction that occurs. Based on the reaction, state the nature (acidic/basic) of copper oxide.

Define the term "power of accommodation" of human eye.

What happens to the image distance in the eye when we increase the distance of an object from the eye?

Name the muscles of the eye responsible for the power of accommodation.

Explain the role of the part of human eye responsible for power of accommodation of human eye. 

Study the picture given below showing three food chains (a), (b) and (c) and answer the following questions:

1. Name the type of ecosystems that exist in food chains (b) and (c).
2. The first trophic level in all food chains is producers. Why? What percentage of solar energy do these producers capture for their use?
3. Why are the arrows shown in the diagram in one direction only and not vice versa? Justify.

How is the sex of a newborn individual determined in different species of animals? Give three examples to support your answer.

Name the oxidising agent used in the conversion of ethanol to ethanoic acid.

Write the chemical equation for the ethanol to ethanoic acid of an oxidation reaction.

How is ethanol to ethanoic acid an oxidation reaction different from the reaction in which ethanol burns in the presence of oxygen?

How is a solenoid prepared?

Differentiate between a circular coil and a solenoid.

Draw the pattern of magnetic field lines of a solenoid through which a steady current flows. What does the pattern of field lines inside the solenoid indicate?

Explain with the help of a labelled diagram, the process of reproduction in Hydra by budding. Name the cells used for reproduction in this process.

List two roles of Seminal vesicles and prostate gland in the human reproductive system.

List two roles of the Oviduct in the human reproductive system.

List two roles of the Testis in the human reproductive system.

When lead nitrate is heated strongly in a boiling tube, two gases are liberated and a solid residue is left behind in the test tube.

1. Name the type of chemical reaction and define it.
2. Write the name and formula of the coloured gas liberated.
3. Write the balanced chemical equation for the reaction.
4. Name the residue left in the test tube and state the method of testing its nature (acidic/basic).

Write balanced chemical equation for the following word equation.

Lead nitrate + Potassium iodide → Lead iodide + Potassium nitrate

Is this a double displacement reaction? Justify your answer. Name the compound precipitated and write the ions present in it.

Write the method of preparation of Ca(OH)₂. What happens when CO₂ is passed through it? Write balanced chemical equation for the reaction involved.

The variation of image distance (v) with object distance (u) for a convex lens is given in the following observation table. Analyse it and answer the questions that follow:

1. Without calculation, find the focal length of the convex lens. Justify your answer.
2. Which observation is not correct? Why? Draw ray diagram to find the position of the image formed for this position of the object.
3. Find the approximate value of magnification for u = – 30 cm.

Define the term principal axis of a lens.

Draw a ray diagram to show what happens when a ray of light parallel to the principal axis of a concave lens passes through it.

The focal length of a concave lens is 20 cm. At what distance from the lens should a 5 cm tall object be placed so that its image is formed at a distance of 15 cm from the lens? Also calculate the size of the image formed.

Define the following: 

Reflex arc  

Why have reflex arcs evolved in animals? 

Trace the sequence of events which occur when you suddenly touch a hot object.

Name the part of the nervous system which helps in communication between the central nervous system and other parts of the body.

What are the two components of the central nervous system?

The leaves of the 'chhui-mui' plant begin to fold up and droop in response to a stimulus. Name the stimulus and write the cause for such a rapid movement. Is there any growth involved in the movement?

Define geotropism.

What is meant by ‘positive geotropism’ and ‘negative geotropism’? Give one example of each type. Draw a labelled diagram to illustrate your answer, indicating the plant part, which shows positive geotropism, and the plant part, which shows negative geotropism.

Study the following circuit:

On the basis of this circuit, answer the following questions:

i. Find the value of total resistance between the points A and B.

ii. Find the resistance between the points B and C.

iii. Calculate the current drawn from the battery, when the key is closed

OR

iii. In the above circuit, the 16Ω resistor or the parallel combination of two resistors of 8 Ω, which one of the two will have more potential difference across its two ends? Justify your answer.

Three metal samples of magnesium, aluminium and iron were taken and rubbed with sandpaper. These samples were then put separately in test tubes containing dilute hydrochloric acid. Thermometers were also suspended in each test tube so that their bulbs dipped in the acid. The rate of formation of bubbles was observed. The above activity was repeated with dilute nitric acid and the observations were recorded.

Answer the following questions:

(i) When the activity was done with dilute hydrochloric acid, then in which one of the test tubes was the rate of formation of bubbles the fastest and the thermometer showed the highest temperature?

(ii) Which metal did not react with dilute hydrochloric acid? Give reason.

(iii) Why is hydrogen gas not evolved when a metal reacts with dilute nitric acid? Name the ultimate products formed in the reaction.

OR

Name the type of reaction on the basis of which the reactivity of metals is decided. You have two metals X and Y. How would you decide which is more reactive than the other?

Kidneys are vital organs for survival. Several factors like infections, injury or restricted blood flow to kidneys reduce the activity of kidneys. This leads to the accumulation of poisonous wastes in the body, which can even lead to death. In case of kidney failure, an artificial kidney can be used. An artificial kidney is a device to remove waste products from the blood through dialysis.

i. a. Name the artery that brings oxygenated blood to the kidney.

b. Name the cluster of the thin-walled blood capillaries present in the Bowman's capsule.

ii. In the human excretory system, name the organ which stores urine. Is this organ under hormonal control or nervous control?

iii. List two major steps involved in the formation of urine and state in brief their functions.

OR

iii. In which part of the nephron does selective reabsorption take place? List the factors which the amount of water reabsorbed depends on.