Samacheer Education

Science

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Samacheer kalvi 10th Science Important Questions

10th Samacheer Kalvi Topics Covered – Science 1

1. 10th 2 Mark Questions.

2. 10th 4 Mark Questions.

3. 10th Numerical Problems.

4. 10th 7 Mark Questions.

5. Repeated Numerical Problems with Answers

10th Samacheer Kalvi Topics Covered – Science 2

1. 10th 2 Mark Questions.

2. 10th 4 Mark Questions.

3. 10th 7 Mark Questions.

                                                                S1 – IMPORTANT 2 MARKS

S1 – CHAPTER – 1

1. Define inertia. Give its classification.

2. Classify the types of force based on their application.

3. Differentiate mass and weight.

4. Define moment of a couple.

5. State the principle of moments.

6. State Newton’s second law.

7. Why a spanner with a long handle is preferred to tighten screws in heavy vehicles?

8. While catching a cricket ball the fielder lowers his hands backwards. Why?

9. How does an astronaut float in a space shuttle?

S1 – CHAPTER – 2

1. What is refractive index?

2. State Snell’s law.

3. Draw a ray diagram to show the image formed by a convex lens when the object is placed between F and 2F.

4. Define dispersion of light

5. What are the causes of ‘Myopia’?

6. Why does the sky appear in blue colour?

7. Why are traffic signals red in colour?

S1 – CHAPTER – 3

1. Define one calorie.

2. What is co-efficient of cubical expansion?

3. State Boyle’s law

4. State-the law of volume

5. Distinguish between ideal gas and real gas.

6. What is co-efficient of real expansion?

7. What is co-efficient of Apparant expansion?

S1 – CHAPTER – 4

1. Why is tungsten metal used in bulbs, but not in fuse wires?

2. Name any two devices, which are working on the heating effect of the electric current.

3.  Define the Unit of Current.

S1 – CHAPTER – 5

1. What is the minimum distance needed for an echo?

2. What will be the frequency sound having 0.20 m as its wavelength, when it travels with a speed of 331 ms–1?

3. Name three animals, which can hear ultrasonic vibrations.

S1 – CHAPTER – 6

1. Write any three features of natural and artificial radioactivity.

2. Define critical mass.

3. Define one roentgen.

4. State Soddy and Fajan’s displacement law.

5. Give the function of control rods in a nuclear reactor.

6. What is stellar energy?

7. Give any two uses of radio isotopes in the field of agriculture?

S1 – CHAPTER – 7

1. Define: Relative atomic mass.

2. Define: Atomicity

3. Give any two examples for hetero diatomic molecules.

S1 – CHAPTER – 8

1. What is rust? Give the equation for formation of rust.

2. State two conditions necessary for rusting of iron.

S1 – CHAPTER – 9

1. Define the term: Solution

2. What is mean by binary solution

3. Give an example each i) gas in liquid ii) solid in liquid iii) solid in solid iv) gas in gas

4. What is aqueous and non-aqueous solution? Give an example. 

5. The aquatic animals live more in cold region. Why?

6. Define Hydrated salt.

7. Classify the following substances into deliquescent, hygroscopic.
Conc. Sulphuric acid, Copper sulphate penta hydrate, Silica gel, Calcium chloride, and Gypsum salt.

S1 – CHAPTER – 10

1. Why does the reaction rate of a reaction increase on raising the temperature?

2. Define combination reaction. Give one example for an exothermic combination reaction.

3. Differentiate reversible and irreversible reactions.

S1 – CHAPTER – 11

1. Name the simplest ketone and give its structural formula.

2. Classify the following compounds based on the pattern of carbon chain and give their structural formula: (i) Propane (ii) Benzene (iii) Cyclobutane (iv) Furan

3. How is ethanoic acid prepared from ethanol? Give the chemical equation.

Differentiate soaps and detergents.

                                              S1 – IMPORTANT – 4 MARKS

S1 – CHAPTER – 1

1. What are the types of inertia? Give an example for each type.

2. Deduce the equation of a force using Newton’s second law of motion. 

3. Describe rocket propulsion.

S1 – CHAPTER – 2

1. List any five properties of light

2. Differentiate the eye defects: Myopia and Hyper metropia

3. Explain the construction and working of a ‘Compound Microscope’.

4. State Rayleigh’s law of scattering. (OR) 7MARKS

5. Differentiate convex lens and concave lens. (OR) 7 MARKS

S1 – CHAPTER – 4

1. State Ohm’s law.

2. Distinguish between the resistivity and conductivity of a conductor.

3. What connection is used in domestic appliances and why?

S1 – CHAPTER – 5

1. Why does sound travel faster on a rainy day than on a dry day?

2. Why does an empty vessel produce more sound than a filled one?

3. Explain why, the ceilings of concert halls are curved.

4. Mention two cases in which there is no Doppler effect in sound?

S1 – CHAPTER – 9

1. Write notes on i) saturated solution ii) unsaturated solution

2. Write notes on various factors affecting solubility.

3. In what way hygroscopic substances differ from deliquescent substances.

S1 – CHAPTER – 10

1. Explain the factors influencing the rate of a reaction

2. How does pH play an important role in everyday life?

S1 – CHAPTER – 11

1. What is called homologous series? Give any three of its characteristics?

2. Arrive at, systematically, the IUPAC name of the compound: CH3–CH2–CH2–OH.

3. How is ethanol manufactured from sugarcane?

4. Give the balanced chemical equation of the following reactions:

(i) Neutralization of NaOH with ethanoic acid.

(ii) Evolution of carbon dioxide by the action of ethanoic acid with NaHCO3.

(iii) Oxidation of ethanol by acidified potassium dichromate.

(iv) Combustion of ethanol.

S1 – IMPORTANT NUMERICAL PROBLEMS

S1 – CHAPTER – 1

1. If a 5 N and a 15 N forces are acting opposite to one another. Find the resultant force and the direction of action of the resultant force.

2. A mechanic unscrew a nut by applying a force of 140 N with a spanner of length 40 cm. What should be the length of the spanner if a force of 40 N is applied to unscrew the same nut?

3. The ratio of masses of two planets is 2:3 and the ratio of their radii is 4:7 Find the ratio of their accelerations due to gravity.

S1 – CHAPTER – 2

1. An object is placed at a distance 20cm from a convex lens of focal length 10cm. Find the image distance and nature of the image.

2. An object of height 3cm is placed at 10cm from a concave lens of focal length 15cm. Find the size of the image.

3. The eyes of the nocturnal birds like owl are having a large cornea and a large pupil. How does it help them? size of the image.

S1 – CHAPTER – 3

1. Find the final temperature of a copper rod. Whose area of cross section changes from 10 m2 to 11 m2 due to heating. The copper rod is initially kept at 90 K. (Coefficient of superficial expansion is 0.0021 /K)

2. If you keep ice at 0° C and water at 0°C in either of your hands, in which hand you will feel more chillness? Why?

S1 – CHAPTER – 4

1. How many electrons are passing per second in a circuit in which there is a current of 5 A?

S1 – CHAPTER – 5

1. Air temperature in the Rajasthan desert can reach 46°C. What is the velocity of sound in air at that temperature? (V0 = 331 ms–1)

2. The thunder of cloud is heard 9.8 seconds later than the flash of lightning. If the speed of sound in air is 330 ms–1, what will be the height of the cloud?

S1 – CHAPTER – 6

1. A cobalt specimen emits induced radiation of 75.6 millicurie per second. Convert this disintegration in to becquerel (one curie = 3.7 × 1010 Bq

S1 – CHAPTER -7

1. How many grams are there in the following?

     i. 2 moles of hydrogen molecule, H2

    ii. 3 moles of chlorine molecule, Cl2

   iii. 5 moles of sulphur molecule, S8

   iv. 4 moles of phosphorous molecule, P4.

2.  Calculate the number of moles in

i) 27g of Al ii) 1.51 × 1023 molecules of NH4Cl

3. Calcium carbonate is decomposed on heat­ing in the following reaction

CaCO3 → CaO + CO2

i.   How many moles of Calcium carbonate are involved in this reaction?

ii. Calculate the gram molecular mass of calcium carbonate involved in this reaction

iii. How many moles of CO2 are there in this equation?

S1 – CHAPTER – 8

1. A is a silvery white metal. A combines with O2 to form B at 800oC, the alloy of A is used in making the aircraft. Find A and B

2. The electronic configuration of metal A is 2,8,18,1.

The metal A when exposed to air and moisture forms B a green layered compound. A with con. H2SO4 forms C and D along with water. D is a gaseous compound. Find A,B,C and D.

3. A is a reddish brown metal, which combines with O2 at < 1370 K gives B, a black coloured compound. At a temperature > 1370 K, A gives C which is red in colour. Find A, B and C with reaction.

S1 – CHAPTER – 9

1. A solution is prepared by dissolving 45 g of sugar in 180 g of water. Calculate the mass percentage of solute.

2.  ‘A’ is a blue coloured crystaline salt. On heating it loses blue colour and to give ‘B’. When water is added, ‘B’ gives back to ‘A’. Identify A and B, write the equation.

3.  a) What happens when MgSO4.7H2O is heated? Write the appropriate equation

      b) Define solubility

S1 – CHAPTER -10

1. Calculate the pH of 1.0 ×10–4 molar solution of HNO3.

2. What is the pH of 1.0 × 10–5 molar solution of KOH?

3. The hydroxide ion concentration of a solution is 1 × 10–11M. What is the pH of the solution?

S1 – CHAPTER – 11

1. The molecular formula of an alcohol is C4H10O. The locant number of its –OH group is 2

(i) Draw its structural formula.

(ii) Give its IUPAC name.

(iii) Is it saturated or unsaturated?

2. An organic compound ‘A’ is widely used as a preservative and has the molecular formula C2H4O2. This compound reacts with ethanol to form a sweet smelling compound ‘B’.

(i) Identify the compound ‘A’.

(ii) Write the chemical equation for its reaction with ethanol to form compound ‘B’.

(iii) Name the process.

                                      S1 – IMPORTANT – 7 MARKS

S1 – CHAPTER – 1

1. State and prove the law of conservation of linear momentum.

2. Give the applications of universal law gravitation.

S1 – CHAPTER – 3

1. Derive the ideal gas equation.

2. Explain the experiment of measuring the real and apparent expansion of a liquid with a neat diagram.

S1 – CHAPTER – 4

1. a) What is meant by electric current?

b) Name and define its unit.

c) Which instrument is used to measure the electric current? How should it be connected in a circuit?

2. a) State Joule’s law of heating.

b) An alloy of nickel and chromium is used as the heating element. Why?

c) How does a fuse wire protect electrical appliances?

3. a) What are the advantages of LED TV over the normal TV?

b) List the merits of LED bulb.

S1 – CHAPTER – 5

1. a) What do you understand by the term ‘ultrasonic vibration’?

b) State three uses of ultrasonic vibrations.

c) Name three animals which can hear ultrasonic vibrations.

2. What is an echo?

a) State two conditions necessary for hearing an echo.

b) What are the medical applications of echo?

c) How can you calculate the speed of sound using echo?

S1 – CHAPTER – 6

1. Explain the process of controlled and uncontrolled chain reactions.

2. Compare the properties of alpha, beta and gamma radiations.

3. What is a nuclear reactor? Explain its essential parts with their functions.

S1 – CHAPTER – 7

1. Give the salient features of “Modern atomic theory”.

2. Derive the relationship between Relative molecular mass and Vapour density.

S1 – CHAPTER – 8

1. Explain smelting process.

Repeated Numerical Problems with Answers

1. Two bodies have a mass ratio of 3:4.The force applied on the bigger mass produces an acceleration of 12 ms-2.What could be the acceleration of the other body, if the same force acts on it.

  Mass ratio of the bodies = 3:4 and the same force is (m1:m2) acting on the body and

a2 = 12 ms-2.

  (i.e) m1a1 = m2a2

   m1/m2 =  a2/a1  

   ¾  = a2/a1

   a1 = 4/3 * 12

   a1 = 16 ms-2.

2. The ratio of masses of two planets is 2:3 and the ratio of their radii is 4:7 Find the ratio of their accelerations due to gravity.

The ratio of masses of two planets m1 : m2 = 2 : 3

The ratio of radii of two planets R1 : R2 = 4 : 7

Formula:

 g = GM / R2

 g1 / g2 = M1/M2 * R2 2 / R2 1

 2/3 * 72 / 42

 2*49/3*16 = 98/48

 g1/g2 = 49/24.

3. An object of height 3cm is placed at 10cm from a concave lens of focal length 15cm. Find the size of the image.

Given that,

Height h = 3cm

Distance u = -15

Radius = 10cm

Now, the focus

 F = r/2

F = 10/2 = 5cm

Now, by using mirror equation

1/f = 1/v + 1/u

1/5 = 1/v – 1/15

1/v = 1/5 + 1/15

V = 4cm

So, the image will be formed between focus and pole.

Now, the magnification is m = -v/u

M = 4/15

Now, m = h’/h’

4/15 = h/3

h– = 12/15

h’ = 0.8

4. What will be the frequency sound having 0.20 m as its wavelength, when it travels with a speed of 331 ms-1 ?

Speed v = 331 m/s

Let the wavelength be ⁁ = 0.2m

Let the frequency be n

Frequency n = v/⁁ = 331/0.2 = 3310/2

Frequency = 1655Hz.

5. Air temperature in the Rajasthan desert can reach 46°C. What is the velocity of sound in air at that temperature? (V0 = 331 ms–1)

Velocity of sound, Vo = 331ms-1

Air temperature, T = 46oC

Velocity of sound in air temperature v = (vo + 0.61T)ms-1

=331 + (0.61 * 46)

=331 + 28.06

Vt = 359.06 ms-1.

6. Calculate the number of moles in 46 g of sodium.

Number of Moles = (Mass of element / Atomic mass of the element)

= 46/23

=2 moles of sodium.

7. Calculate the number of moles in i) 27g of Al ii) 1.51 × 1023 molecules of NH4Cl

Number of moles = Mass / Atomic mass

Number of moles in 27g of Al = 27 / 27 = 1 mole.

Number of moles = number of molecules / Avogadro number

= 1.51 * 1023 / 6.023 * 1023 = 0.25 moles.

8. A is a reddish brown metal, which combines with O2 at < 1370 K gives B, a black coloured compound. At a temperature > 1370 K, A gives C which is red in colour. Find A,B and C with reaction.

2 Cu + O2 →˂1370K 2 CuO (B)

4 Cu + O2 →˂1370K 2 Cu2O (C)

A – Copper; B – Cupric oxide; C – Cuprous oxide.

9. A is a silvery white metal. A combines with O2 to form B at 800oC, the alloy of A is used in making the aircraft. Find A and B

    A – Silvery white metal – Aluminium

    4 Al + 3O2 → 2 Al2O3 (B)

    The alloys of aluminium, duralumin and Magnalium are used in making the aircraft.  

   A – Aluminium; B – Aluminium oxide.

10. The electronic configuration of metal A is 2,8,18,1. The metal A when exposed to air and moisture forms B a green layered compound. A with con. H2SO4 forms C and D along with water. D is a gaseous compound. Find A,B,C and D.

  • The electronic configuration of metal (A) is 2,8,18,1. A is copper (Z = 29).
  • (A) copper exposed to air and moisture forms a green layered compound (B) that is copper carbonate. 2 Cu + O2 + CO2 + H2O → CuSO3.Cu(OH)2.
  • Copper (A) reacts with conc.H2SO4 to give copper sulphate (C) and sulphur dioxide (D). Cu + conc.2H2SO4 → CuSO4 + SO2 ↑ + 2H2O.
         A     Copper     Cu
         BCopper carbonateCuCO3.Cu(OH)2
         C Copper sulphateCuSO4
         DSulphate dioxideSO2

11. What happens when MgSO4.7H2O is heated? Write the appropriate equation

MgSO4.7H2O has water of crystallization is 7. When magnesium sulphate heptahydrate crystals are gently heated, it loses seven water molecules and becomes anhydrous magnesium Sulphate.

MgSO4.7H2O                                     Heating               MgSO4 + 7H2O

Magnesium sulphate heptahydrate                  ↔              Anhydrous magnesium sulphate

                                                             Cooling

12.  A solution is prepared by dissolving 45 g of sugar in 180 g of water. Calculate the mass percentage of solute.

Mass of the solute (sugar) = 45g

Mass of solvent (water) = 180g

Formula,

Mass % of solute (sugar) = mass of the solute / mass of the solute + mass of the solvent.

=  (45/(45+180))    * 100                  

= ( 45 / 225 )  * 100

= 20%

The mass percentage of solute = 20%.

13. ‘A’ is a blue coloured crystaline salt. On heating it loses blue colour and to give ‘B’. When water is added, ‘B’ gives back to ‘A’. Identify A and B, write the equation.

Since, ‘A’ is a blue coloured crystalline salt, it is CUSO4.5H2O (Blue vitriol).

On heating, it loses all five water molecules and becomes colourless anhydrous CUSO4.

  CUSO4.5H2O        heating          CUSO4              +           5H2O

          (A)                       ↔            anhy.copper sulphate               colourless (B)      

                                   cooling

When water is added ‘B’ gives back A.

14. When an aqueous solution of potassium chloride is added to an aqueous solution of silver nitrate, a white precipitate is formed. Give the chemical equation of this reaction.

KCL(aq) + AgNO3(aq) → AgCl (s) + KNO3(aq)

Formation of white precipitated by the above reaction is due to formation of silver chloride (AgCl)

15. a) Calculate the pH of 1.0 ×10-4 molar solution of HNO3.

b) The hydroxide ion concentration of a solution is 1 × 10-11 M. What is the pH of the solution?

pH = – log (H+)

HNO3 → H+ + NO3

pH = – log (1*10-4)

= – (-4) log10 10 = 4

pH = 4

(OH–) = 1* 10-11 M

pOH = – log (OH–)

= – log (1 * 10-11)

= – log 101 – log10 10-11

= – (-11) log1010 = 11

pOH = 11

pH + poh = 14

pH = 14 – 11

pH = 3

16. Give the balanced chemical equation of the following reactions:

(i) Neutralization of NaOH with ethanoic acid.

(ii) Evolution of carbon dioxide by the action of ethanoic acid with NaHCO3.

  • Neutralization reaction:

CH3COOH    +       NaOH          → CH3COONa + H2O

   Acetic acid              sodium hydroxide              sodium acetate        

  • Evolution of carbon dioxide :

CH3COOH + NaHCO3 → CH3COONa + H2O + CO2.

Science – 2

S2 – IMPORTANT 2 MARKS

S2 – CHAPTER – 12

  1. Give an account on vascular bundle of dicot stem.
  2. Write a short note on mesophyll.
  3. Draw and label the structure of oxysomes. 
  4. What is photosynthesis and where in a cell does it occur?
  5. What is respiratory quotient?
  6. Write the reaction for photosynthesis?

S2 – CHAPTER – 13

  1. How does leech respire?
  2. Write the dental formula of rabbit.
  3. How is diastema formed in rabbit?
  4. What does CNS stand for?
  5. Why is the teeth of rabbit called heterodont?
  6. How does leech suck blood from the host?

S2 – CHAPTER – 14

  1. Name two layered protective covering of human heart.
  2. What is the shape of RBC in human blood?
  3. Why is the colour of the blood red ?
  4. Mention the artery which supplies blood to the heart muscle.

S2 – CHAPTER – 15

  1. Name the parts of the hind brain.
  2. Which acts as a link between the nervous system and endocrine system?
  3. Define reflex arc.

S2 – CHAPTER – 16

  1. What are synthetic auxins? Give examples.
  2. What is bolting? How can it be induced artificially?
  3. Bring out any two physiological activities of abscisic acid
  4. What are chemical messengers?

S2 – CHAPTER – 17

  1. Define triple fusion.
  2. Name the secondary sex organs in male
  3. How can menstrual hygiene be maintained during menstrual days?
  4. Why are family planning methods not adopted by all the people of our country?
  5.  Identify the parts A, B, C and D

S2 – CHAPTER – 18

  1. Why did Mendel select pea plant for his experiments?
  2. What do you understand by the term phenotype and genotype?
  3. What are allosomes?
  4. What are Okazaki fragments?
  5. Explain the structure of a chromosome.

S2 – CHAPTER – 19

  1. Which organism is considered to be the fossil bird?
  2. What is the study of fossils called?

S2 – CHAPTER – 20

  1. Define genetic engineering.
  2. Name the types of stem cells.
  3. What are transgenic organisms?
  4. State the importance of biofertiliser.

S2 – CHAPTER – 21

  1. What are psychotropic drugs?
  2. What is metastasis?

S2 – CHAPTER – 22

  1. Solar energy is a renewable energy. How?
  2. How are e-wastes generated?

S2 – CHAPTER – 23

  1. What is Scratch?
  2. Write a short note on editor and its main parts?
  3. What is Stage?
  4. What is Sprite?

                                        S2 – IMPORTANT – 4 MARKS

S2 – CHAPTER – 12

  1. Differentiate the following a) Monocot root and Dicot root b) Aerobic and Anaerobic respiration
  2. Describe and name three stages of cellular respiration that aerobic organisms use to obtain energy from glucose.

S2 – CHAPTER – 13

  1. Why are the rings of cartilages found in trachea of rabbit?
  2. List out the parasitic adaptations in leech.

S2 – CHAPTER – 14

  1. Describe the structure and working of the human heart.
  2. What is the importance of valves in the heart?
  3. Who discovered Rh factor? Why was it named so?
  4. How are arteries and veins structurally different from one another?
  5. Why is the Sinoatrial node called the pacemaker of heart?
  6. Differentiate between systemic circulation and pulmonary circulation.
  7. Guard cells are responsible for opening and closing of stomata.
  8. The walls of the right ventricle are thicker than the right auricles.
  9. Mature RBC in mammals do not have cell organelles.

S2 – CHAPTER – 15

  1. Voluntary and involuntary actions.
  2. Medullated and non-medullated nerve fibre.

S2 – CHAPTER – 16

  1. Write the physiological effects of gibberellins.
  2. Where are estrogens produced? What is the role of estrogens in the human body?

S2 – CHAPTER – 19

  1. Define Ethnobotany and write its importance.
  2. How can you determine the age of the fossils?

S2 – CHAPTER – 20

  1. Distinguish between a) somatic gene therapy and germ line gene therapy b) undifferentiated cells and differentiated cells
  2. State the applications of DNA fingerprinting technique.
  3. Differentiate between outbreeding and inbreeding.

S2 – CHAPTER – 21

  1. What are the contributing factors for Obesity?
  2. How is a cancer cell different from a normal cell?
  3. Differentiate between Type-1 and Type-2 diabetes mellitus.
  4. What precautions can be taken for preventing heart diseases?

S2 – CHAPTER – 22

  1. What is the importance of rainwater harvesting?
  2. What are the advantages of using biogas?
  3. What are the consequences of deforestation?

                                       S2 – IMPORTANT – 7 MARKS

S2 – CHAPTER – 13

  1. How does locomotion take place in leech?
  2. Explain the male reproductive system of rabbit with a labelled diagram.

S2 – CHAPTER – 14

  1. How does locomotion take place in leech?
  2. Explain the male reproductive system of rabbit with a labelled diagram.
  3. Differentiate between systole and diastole. Explain the conduction of heart beat.
  4. Enumerate the functions of blood.

S2 – CHAPTER – 15

  1. With a neat labelled diagram explain the structure of a neuron.
  2. Describe the structure of spinal cord.
  3. Illustrate the structure and functions of brain.

S2 – CHAPTER – 17

  1. What are the phases of menstrual cycle? Indicate the changes in the ovary and uterus.

S2 – CHAPTER – 18

  1. Explain with an example the inheritance of dihybrid cross. How is it different from monohybrid cross?
  2. How is the structure of DNA organised? What is the biological significance of DNA?

S2 – CHAPTER – 20

     1. With a neat labelled diagram explain the techniques involved in gene cloning.

     2. Discuss the importance of biotechnology in the field of medicine.

     3. What are the effects of hybrid vigour in animals.

S2 – CHAPTER – 21

  1. Suggest measures to overcome the problems of an alcoholic.

S2 – CHAPTER – 22

  1. How does rainwater harvesting structures recharge ground water?
  2. How will you prevent soil erosion?
  3. Enumerate the importance of forest.
  4. What are the consequences of soil erosion?