Science Class X

An element X has mass number 35 and the number of neutrons is 18

• Periodic Classification of Elements (C10)

An element "X" has mass number 35 and the number of neutrons is 18. Identify the group number and period of "X".

Define excretion. Name the basic filtration unit present in the kidney

• Life Processes (C10)

(a) Define excretion.

(b) Name the basic filtration unit present in the kidney.

(c) Draw excretory system in human beings and label the following organs of excretory system which perform following functions:
(i) form urine
(ii) is a long tube which collects urine from kidney
(iii) store urine until it is passed out

How is copper extracted from its sulphide ore

• Metals & Non-metals (C10)

How is copper extracted from its sulphide ore? Explain the various steps supported by chemical equations. Draw labelled diagram for the electrolytic refining of copper.

Draw the structural formulae of all the possible isomers of C3H6O

• Carbon & its Compounds (C10)

Draw the structural formulae of all the possible isomers of the compound with the molecular formula C₃H₆O and also give their electron dot structures.

Name the process by which an amoeba reproduces

• Science Practical (C10)

Name the process by which an amoeba reproduces. Draw the various stages of its reproduction in a proper sequence.

A student observed a permanent slide showing asexual reproduction in yeast

• Science Practical (C10)

A student observed a permanent slide showing asexual reproduction in yeast. Draw diagrams of the observations he must have made from the slide. Name the process also.

You are given balls and stick model of six carbon atoms and fourteen hydrogen atoms

• Carbon & its Compounds (C10)

You are given balls and stick model of six carbon atoms and fourteen hydrogen atoms and sufficient number of sticks. In how many ways one can join the models of six carbon atoms and fourteen hydrogen atoms to form different molecules of C₆H₁₄.

Name the electric device that converts mechanical energy into electrical energy

• Magnetic Effects (C10)

Name the electric device that converts mechanical energy into electrical energy. Draw the labelled diagram and explain the principle involved in this device.

Draw a circuit diagram of an electric circuit containing a cell

• Electricity (C10)

Draw a circuit diagram of an electric circuit containing a cell, a key, an ammeter, a resistor of 4Ω in series with a combination of two resistors (8Ω each) in parallel and a voltmeter across parallel combination. Each of them dissipate maximum energy and can withstand a maximum power of 16W without melting. Find the maximum current that can flow through the three resistors.

With the help of a labelled circuit diagram wire describe an activity

• Magnetic Effects (C10)

With the help of a labelled circuit diagram wire describe an activity to illustrate the pattern of the magnetic field lines around a straight current carrying long conducting wire.

1. Name the rule that is used to find the direction of magnetic field associated with a current carrying conductor.
2. Is there a similar magnetic field produced around a thin beam of moving (a) alpha particles and (b) neutrons? Justify your answer.

Write two observations when lead nitrate is heated in a test tube

• Chemical Reactions & Equations (C10)

(i) Write two observations when lead nitrate is heated in a test tube.

(ii) Name the type of reaction.

(iii) Write a balanced chemical equation to represent the above reaction.

A compound X of sodium is used as an antacid

• Acids, Bases & Salts (C10)

A compound ‘X’ of sodium is used as an antacid and it decomposes on strong heating.

1. Name the compound ‘X’ and give its chemical formula.
2. Write a balanced chemical equation to represent the decomposition of ‘X’.
3. Give one use of compound ‘X’ besides an antacid.

You are provided with 90 mL of distilled water

• Acids, Bases & Salts (C10)

You are provided with 90 mL of distilled water and 10 mL of concentrated sulphuric acid to prepare dilute sulphuric acid.

1. What is the correct way of preparing dilute sulphuric acid? Give reason.
2. How will the concentration of H₃O⁺ ions change on dilution?

Two elements X and Y have atomic numbers 12 and 16 respectively

• Periodic Classification of Elements (C10)

Two elements X and Y have atomic numbers 12 and 16 respectively. To which period of the modern periodic table do these two elements belong? What type of bond will be formed between them and why? Also give the chemical formula of the compound formed.

Create a terrestrial food chain depicting four trophic levels

• Our Environment (C10)

(i) Create a terrestrial food chain depicting four trophic levels.

(ii) Why do we not find food chains of more than four trophic levels in nature?

How will you create an artificial aquatic ecosystem

• Our Environment (C10)

How will you create an artificial aquatic ecosystem, which is self-sustainable?

Explain giving reasons the bending of the shoot tip of a plant

• Control & Coordination (C10)

Explain giving reasons the bending of the shoot tip of a plant towards light source coming from one side of the plant.

It is desired to obtain an erect image of an object

• Reflection & Refraction (C10)

It is desired to obtain an erect image of an object, using concave mirror of focal length of 12 cm.

1. What should be the range of the object distance in the above case?
2. Will the image be smaller or larger than the object? Draw a ray diagram to show the formation of image in this case.
3. Where will the image of this object be, if it is placed 24 cm in front of the mirror?

A narrow beam of white light is shown to pass through a triangular glass prism

• Human Eye & Colourful World (C10)

In the figure given below, a narrow beam of white light is shown to pass through a triangular glass prism. After passing through the prism, it produces a spectrum XY on the screen.

1. Name the phenomenon.
2. State the colours seen at X and Y.
3. Why do different colours of white light bend at different angles through a prism?

What is visible spectrum

• Human Eye & Colourful World (C10)

(i) What is visible spectrum?

(ii) Why is red used as the stopping light at traffic signals?

(iii) Two triangular glass prisms are kept together connected through their rectangular side. A light beam is passed through one side of the combination. Will there be any dispersion? Justify your answer.

Metal X is found in nature as its sulphide XS

• Metals & Non-metals (C10)

Metal X is found in nature as its sulphide XS. It is used in the galvanisation of iron articles. Identify the metal X. How will you convert this sulphide ore into the metal? Explain with equations.

Sodium or potassium metals are kept immersed under kerosene

• Metals & Non-metals (C10)

State the reason for the following: Sodium or potassium metals are kept immersed under kerosene.

Calcium does not occur in free state in nature

• Metals & Non-metals (C10)

State the reason for the following: Calcium does not occur in free state in nature.

Hydrogen gas is not evolved when most metals react with nitric acid

• Metals & Non-metals (C10)

State the reason for the following: Hydrogen gas is not evolved when most metals react with nitric acid.

An iron strip dipped in a blue copper sulphate solution

• Metals & Non-metals (C10)

State the reason for the following: An iron strip dipped in a blue copper sulphate solution turns the blue solution pale green.

Aluminium oxide is called an amphoteric oxide

• Metals & Non-metals (C10)

State the reason for the following: Aluminium oxide is called an amphoteric oxide.

The formulae of four organic compounds are

• Carbon & its Compounds (C10)

The formulae of four organic compounds are given below:

• A: C₂H₄
• B: CH₃COOH
• C: C₂H₅OH
• D: C₂H₆

Conductor is cut into four equal parts. What will be the new resistivity

• Electricity (C10)

(i) Consider a conductor of resistance ‘R’, length ‘L’, thickness ‘d’ and resistivity ‘ρ’. Now this conductor is cut into four equal parts. What will be the new resistivity of each of these parts? Why?

Define catenation

• Carbon & its Compounds (C10)

Define catenation

How does valency of an element vary across a period?

• Periodic Classification of Elements (C10)

How does valency of an element vary across a period?

A lens produces a magnification of -0.5. Is this a converging or diverging lens?

• Reflection & Refraction (C10)

A lens produces a magnification of -0.5. Is this a converging or diverging lens? If the focal length of the lens is 6 cm, draw a ray diagram showing the image formation in this case.

A girl was playing with a thin beam of light from a laser torch

• Reflection & Refraction (C10)

A girl was playing with a thin beam of light from a laser torch by directing it from different directions on a convex lens held vertically. She was surprised to see that in a particular direction, the beam of light continues to move along the same direction after passing through the lens. State the reason for her observation. Draw a ray diagram to support your answer.

On entering in a medium from air, the speed of light becomes half

• Reflection & Refraction (C10)

On entering in a medium from air, the speed of light becomes half of its value in air. Find the refractive index of that medium with respect to air?

A glass slab made of a material of refractive index n1

• Reflection & Refraction (C10)

A glass slab made of a material of refractive index n₁ is kept in a medium of refractive index n₂. A light ray is incident on the slab. Draw the path of the rays of light emerging from the glass slab, if (i) n₁ > n₂ (ii) n₁ = n₂ (iii) n₁ < n₂

The absolute refractive index of Ruby is 1.7

• Reflection & Refraction (C10)

The absolute refractive index of Ruby is 1.7. Find the speed of light in Ruby. The speed of light in vacuum is 3 × 10⁸ m/s.

On heating blue coloured powder of copper (II) nitrate

• Chemical Reactions & Equations (C10)

On heating blue coloured powder of copper (II) nitrate in a boiling tube, black copper oxide, O₂ and a brown gas X is formed.

1. Identify the type of reaction and the gas X.
2. Write balanced chemical equation of the reaction.
3. Write the pH range of aqueous solution of the gas X.

While diluting an acid, why is it recommended that the acid

• Acids, Bases & Salts (C10)

(a) While diluting an acid, why is it recommended that the acid should be added to water and not water to the acid ?

(b) Dry hydrogen chloride gas does not change the colour of dry litmus paper. Why ?

How is sodium hydroxide manufactured in industries

• Acids, Bases & Salts (C10)

How is sodium hydroxide manufactured in industries ? Name the process. In this process a gas X is formed as by-product. This gas reacts with lime water to give a compound Y, which is used as a bleaching agent in the chemical industry. Identify X and Y and write the chemical equation of the reactions involved.

What are amphoteric oxides

• Acids, Bases & Salts (C10)

What are amphoteric oxides ? Give an example. Write balanced chemical equations to justify your answer.

What is a homologous series of carbon compounds

• Carbon & its Compounds (C10)

What is a homologous series of carbon compounds ? Give an example and list its three characteristics.

Distinguishing features between autotrophic nutrition and heterotrophic nutrition

• Life Processes (C10)

List in tabular form three distinguishing features between autotrophic nutrition and heterotrophic nutrition.

What is translocation

• Life Processes (C10)

(a) What is translocation ? Why is it essential for plants ?

(b) Where do the substances in plants reach as a result of translocation ?

What is transpiration? List its two functions

• Life Processes (C10)

What is transpiration ? List its two functions.

What is carpel? Write the function of its various parts

• Reproduction (C10)

What is carpel ? Write the function of its various parts.

A 10 cm tall object is placed perpendicular to the principal axis

• Reflection & Refraction (C10)

A 10 cm tall object is placed perpendicular to the principal axis of a convex lens of focal length 12 cm. The distance of the object from the lens is 18 cm. Find the nature, position and size of the image formed.

Write the essential function performed by ozone at the higher levels

• Our Environment (C10)

Write the essential function performed by ozone at the higher levels of the Earth’s atmosphere ? How is it produced ? Name the synthetic chemicals mainly responsible for the drop of amount of ozone in the atmosphere. How can the use of these chemicals be reduced ?

What are solar cells? Explain the structure of solar panel

• Sources of Energy (C10)

What are solar cells ? Explain the structure of solar panel. List two principal advantages associated with solar cells.

The electrons in the atoms of four elements A, B, C and D

• Periodic Classification of Elements (C10)

The electrons in the atoms of four elements A, B, C and D are distributed in three shells having 1, 3, 5 and 7 electrons respectively in their outermost shells. Write the group numbers in which these elements are placed in the Modern Periodic Table. Write the electronic configuration of the atoms of B and D and the molecular formula of the compound formed when B and D combine.

How does the metallic character of elements vary

• Periodic Classification of Elements (C10)

How does the metallic character of elements vary on moving from

1. left to right in a period,
2. from top to bottom in a group

of the Modern Periodic Table ? Give reason for your answer.

List any three observations which posed a challenge to Mendeleev’s Periodic Law

• Periodic Classification of Elements (C10)

List any three observations which posed a challenge to Mendeleev’s Periodic Law.