100 Important Questions for Class 10 Science 2023 Board Exam Chapter Wise

CBSE Board Class 10 Science Important Questions, Exam Pattern, Preparation & Exam Day Tips are given below.

#1 CHEMICAL REACTIONS & EQUATIONS

• What happens chemically when quicklime is added to water?
• A student burns magnesium ribbon in the lab and observes a white powder falling on the table. What type of reaction has taken place and name the white powder?
• What are the essentials of a chemical reaction?
• How will you test for the gas which is liberated when hydrochloric acid reacts with an active metal?
• What change in colour is observed when white silver chloride is left exposed to sunlight? What type of chemical reaction is this?
• Why is respiration considered as exothermic process?
• What is meant by skeletal equation?
• Identify the type of reaction in the following example: Na2SO4(aq) + BaCl2(aq) —→ BaSO4(s) + 2NaCl(aq)
• Why are bags of chips flushed with nitrogen gas?
• What is precipitation reaction?
• Name a reducing agent that may be used to obtain manganese from manganese dioxide.
• What is thermite reaction?
• When zinc metal reacts with dilute hydrochloric acid then zinc chloride is formed and a gas is released. Can you identify the gas? The conical flask becomes hot, it shows which type of reaction it is? Write the balanced chemical equation.
• What is the brown coloured gas evolved when lead nitrate crystals are heated in a dry test tube?
• Why do we apply paint on iron articles?
• Identify the type of reaction in the following example: Fe(s) + CuSO4(aq) —→ FeSO4(aq) + Cu(s)
• A metal ‘X ‘ left in moist air for a longer time, loses its shiny brown surface and gained a green coat. Why has this happened? Name and give chemical formula of this given coloured compound and identify the metal. List two ways to prevent this process.
• Marble statues often slowly get corroded when kept in open for a long time. Why does this happen?
• What is the significance of a chemical equation? / What information does a chemical equation convey?

#2 ACID, BASES & SALTS

• List the organic acid present in the following objects:
  (a) Citrus Fruits (lemon, orange)
  (b) Sting of bees and ants
  (c) Rancid butter
  (d) Tamarind, grapes, apples
  (e) Apples
  (f) Gastric juice
  (g) Vinegar
  (h) Fats
  (i) Urine
  (j) Sour milk, curd
• State true (✓) or false (✗)
  (a) Heat is evolved during ionisation.
  (b) Solution of glucose in water produces ions.
  (c) Dry ammonia has no effect on litmus paper.
  (d) Higher is the concentration of H(aq), lower is the pH value.
  (e) The concentration of aqueous solutions of acid, base and salt are generally expressed in molarity.
  (f) pH of a solution can vary from 0-14.
  (g) HC1 is a weak acid.
  (h) NaOH is a strong base.
  (i) Curd is alkaline in comparison to fresh milk.
  (j) pH = + log10[(H3O-]
  (k) Distilled water does not conduct electricity.
  (l) Analgesics helps to relieve acidity.
• Identify which of the following chemical formulas is acid, base or salt. Write their corresponding chemical names also.
  (a) HCl
  (b) NaOH
  (c) NaCl
  (d) Ca(NO3)2
  (e) Ca(OH)2
  (f) HNO3
  (g) NH4OH
  (h) (NH4)2SO4
  (i) CuO
  (j) H2SO4
  (k) CuCO3
  (l) H2CO3
  (m) MgO
  (n) Mg3(PO4)2
• Fill in the blanks.
  (a) Turmeric, clove, rose petals are ______ _____ .
  (b) Acids ______ _______ bases to form ________ and water.
  (c) The term pH was coined by _______ .
  (d) Turmeric turns _____ _______ in basic medium.
  (e) ________ ________ is used in softening water.
  (f) String acids show ______ ionisation while weak acids show _______ ionisation.
  (g) Calcium Sulphate hemihydrate is popularly known as _____ ___ _____.
  (h) Acids contain the hydrogen (H+) as the only ______ _______.
  (i) Bases contain the Oxide (O2-) or hydroxide (OH-) radical as the only _______ radical.
• The most commonly used indicator in laboratory is
  (a) Methyl Orange
  (b) Litmus
  (c) Phenolphtalein
  (d) Universal Indicator
• Olfactory indicators are:
  (a) Clove
  (b) Turmeric
  (c) Soap
  (d) Rose Petals
• An element common to all acids is
  (a) Chlorine
  (b) Nitrogen
  (c) Oxygen
  (d) Hydrogen
• Metal carbonate on reaction with dilute acid release
  (a) CO2
  (b) CO
  (c) H2O
  (d) H2
• (Teachers FA manual): ln general, salts
  (a) are ionic compounds
  (b) contain hydrogen ions
  (c) contain hydroxide ions
  (d) turn litmus red
• On passing excess of CO2 gas in an aqueous solution of calcium carbonate, milkiness of the solution
  (a) persists
  (b) fades
  (c) deepens
  (d) disappears
• (FA manual): When magnesium and hydrochloric acid react, they produce
  (a) Oxygen and magnesium chloride
  (b) Chlorine and magnesium oxide
  (c) Hydrogen and magnesium chloride
  (d) Hydrogen and magnesium oxide
• Dissolution of acid or base in water is
  (a) Exothermic
  (b) Endothermic
  (c) Violent
  (d) None of these
• Water contains more H+ ions than OH- ions. In this case, water is
  (a) neutral
  (b) basic
  (c) acidic
  (d) cannot say
• When an acid reacts with a base what compounds are formed?
  (a) water only
  (b) metal oxides only
  (c) a salt only
  (d) a salt and water
• Which of the following is a property of an acid?
  (a) slippery feel
  (b) non-reactive
  (c) sour taste
  (d) strong color
• On diluting an acid concentration of H+ per unit volume
  (a) increases
  (b) decreases
  (c) remains unaffected
  (d) depends on type of acid used.
• What is pH?
  (a) the positive logarithm of the hydroxide ion concentration
  (b) the positive logarithm of the hydrogen ion concentration
  (c) the negative logarithm of the hydroxide ion concentration
  (d) the negative logarithm of the hydrogen ion concentration
• Tartaric acid is the constituent of
  (a) bleaching powder
  (b) baking powder
  (c) washing powder
  (d) plaster of paris
• A solution turns blue litmus red. Its pH value is likely to be
  (a) 4
  (b) 7
  (c) 9
  (d) 12
• What is the name of H2SO3?
  (a) Sulphuric Acid
  (b) Sulphurous Acid
  (c) Sulphite Acid
  (d) Hydrogen Sulphide.
• Which gas is produced by reaction of base with metal ?
  (a) Carbon dioxide
  (b) Dioxygen
  (c) Dihydrogen
  (d) Dinitrogen
• Acid + Metal-oxide → ?
  (a) Base + Water
  (b) Salt + Water
  (c) Base + Salt
  (d) Metal + Salt
• Which of the following is a weak acid?
  (a) Hydrochloric Acid
  (b) Nitric Acid
  (c) Acetic Acid
  (d) Sulphuric Acid
• An indicator is what type of compound?
  (a) reducing agent
  (b) strong base or acid
  (c) weak base or acid
  (d) salt
• Which of the following is strong acid ?
  (a) Acetic acid
  (b) Citric acid
  (c) Nitric acid
  (d) Oxalic acid
• Name the organic acid present in tomato
  (a) Tartaric Acid
  (b) Malic Acid
  (c) Lactic Acid
  (d) Oxalic Acid
• You have been provided with three test tubes. One of them contains distilled water and the other two contain an acidic solution and a basic solution, respectively. If you are given only red litmus paper, how will you identify the contents of each test tube?
• Why should curd and sour substances not be kept in brass and copper vessels?
• Why vinegar is used in pickling?
• Why phenolphthalein is considered acid base indicator?
• (NCERT): Which gas is usually liberated when an acid reacts with a metal? Illustrate with an example. How will you test for the presence of this gas?
• (NCERT): Metal compound A reacts with dilute hydrochloric acid to produce effervescence. The gas evolved extinguishes a burning candle. Write a balanced chemical equation for the reaction if one of the compounds formed is calcium chloride.
• (NCERT): Why do HCl, HNO3 , etc., show acidic characters in aqueous solutions while solutions of compounds like alcohol and glucose do not show acidic character?
• (NCERT): Why does an aqueous solution of an acid conduct electricity?
• Why should acids be handled with care?
• Why does dry HCl gas not change the colour of dry litmus paper
• While diluting an acid, why is it recommended that the acid should be added to water and not water to the acid?
• What is an amphoteric substance?
• On the basis of origin, how acids are classified?
• What are organic acids? Give two examples
• What are mineral acids? Give two examples
• What is the chemical name of Bleaching powder? How it is prepared? List its uses.
• Which acid is used in Cola to give it a biting sharp taste?
• What is gypsum?
• Define Dilution.
• (CBSE 2010): Tooth enamel is one of the hardest substance in our body. How does it undergo damage due to the eating of chocolates and sweets? What should we do to prevent it? / Why does tooth decay start when the pH of the mouth is lower than 5.5?

#3 METALS & NON-METALS

• List any five physical properties of metals.
• Are metals electronegative or electropositive?
• Define Malleability.
• Name a metal which can be cut with a knife?
• Give examples of metals which are found in liquid form at room temperature.
• Define ductility. Give two examples of metals that exhibit this property.
• Give an example of metal which is  i. the best conductor of heat ii. the poor conductor of heat.
• What are metalloids? Give examples of metalloids.
• What are minerals?
• Can metals be extracted from all types of minerals?
• What are ores?
• Define metallurgy.
• Give an example of non-metal which is lustrous.
• Give an example of a non-metal which is hard and has high melting point.
• What is gangue and what is concentration?
• Why do potato chips manufacturers fill the packet of chips with nitrogen gas?
• Name any non-metal which is found in liquid state at room temperature.
• (KVS): You are given two statements a and b, select the correct inference from this: a. Metals conduct heat. b. Diamond is the best conductor of heat.
  i. Hence diamond is a metal
  ii. Statement a is correct
  iii. Statements a and b is correct
  iv. None of the above
• Write differences between metals and non-metals based on physical properties.

#4 CARBON & ITS COMPOUNDS

• What is next homologue of C3H7OH is called?
• What is the molecular formula of the alcohol which can be derived from propane?
• What is meant by the term functional group?
• Give the names of the functional groups: (CBSE 2007)
•          (i) -CHO  (ii)  -C=O
• Give the names of the following functional groups: (CBSE 2007)
•         (i) —OH (ii) —COOH
• Which functional groups always occur at the terminal position of a carbon chain?
• Why a candle flame burns yellow, while a highly-oxygenated gas-fuel flame burns blue?
• Why is the reaction between methane and chlorine considered a substitution reaction? [CBSE 2008]
• Why does Carbon form compounds mainly by covalent bonding?
• Give a chemical test to distinguish between saturated and unsaturated hydrocarbons.
• What do you mean by Octane Rating?
• Two compounds A and B react with each other in the presence of a dehydrating agent to produce an ester. Both react with Na to evolve hydrogen gas. On reaction with Na2CO3 only A evolves CO2. Identify the functional groups present in A and B giving reason for your answer.
• An organic compound ‘X’ is widely used as a preservative in pickles and has a molecular formula C2H2O2. This compound reacts with ethanol to form a sweet smelling compound ‘Y’.
• (NCERT): What would be the electron dot structure of carbon dioxide which has the formula CO2?
• (NCERT): What would be the electron dot structure of a molecule of sulphur which is made up of eight atoms of sulphur? (Hint – The eight atoms of sulphur are joined together in the form of a ring.)
• (NCERT): How many structural isomers can you draw for pentane?
• (NCERT): What are the two properties of carbon which lead to the huge number of carbon compounds we see around us?
• What is Covalent bonding?
• What are Hydrocarbons? Give examples.
• (CBSE 2011): What are saturated hydrocarbons?
• (CBSE 2011): “Saturated hydrocarbons burn with a blue flame while unsaturated hydrocarbons burn with a sooty flame”. Why?
• (CBSE 2011): “Saturated hydrocarbons burn with a blue flame while unsaturated hydrocarbons burn with a sooty flame”. Why?
• What are isomers?
• (NCERT): Why do ionic compounds have high melting points?
• What are the characteristics of Homologue series?
• What is the general formula of Alkanes?
• What is a heteroatom? What is the heteroatom in alcohol functional group?

#5 PERIODIC CLASSIFICATION OF ELEMENTS

• What are the defects in Modern Periodic Table?
• What are the salient features of Modern Periodic Table?
• Two elements X and Y have atomic numbers 12 and 16 respectively. Write the electronic configuration for these elements. To which period of the modern periodic table do these two elements belong? What type of bond will be formed between them and why?
• The present classification of elements is based on which fundamental property of elements?
• Li, Na and K are the elements of a Dobereiner’s Triad. If atomic mass of Li is 7 and that of K is 39. What would be the atomic mass of Na?
• Define Dobereiner’s law of triads.
• Why did Dobereiner’s system of classification fail?
• Explain about position of metalloids in modern periodic table.
• Why does Silicon classified as metalloid?
• State Newland’s law of octaves.
• X and Y are the two elements having similar properties which obey Newlands law of octaves. How many elements are there in between X and Y?
• What are the drawbacks of Newland’s law of octaves?
• What periodic trends  do we observe in terms of atomic radii or atomic sizes in Modern periodic table?
• Name the scientist who proposed modern periodic law? On which fundamental property of elements it is based?
• On what basis did Mendeleev arrange the elements?
• An element R of atomic number 12 combines separately with NO3- and (SO4)2-, (PO4)3- radicals.
• (NCERT): Why do you think the noble gases are placed in a separate group?
• (NCERT): Besides gallium, which other elements have since been discovered that were left by Mendeléev in his Periodic Table? (any two)

#6 LIFE PROCESSES

• Movement is the most important criterion to decide whether something is alive or not. Justify.
• Define Life process and basic of life processes.
• Reason for need of energy while sleeping.
• All living organisms need energy to perform. Explain?
• What is nutrition and what are its nutrients?
• Heterotrophic mode of nutrition and types of heterotrophic Nutrition.
• Name the organelles which contain chlorophyll.
• What is the role of guard cell?
• The mechanism of opening and closing of stomata.
• What is photosynthesis? Explain its process with the help of diagram and chemical equation.
• Raw materials of photosynthesis and list the events occur during photosynthesis.
• What are carbohydrates?
• Conditions necessary for autotrophic nutrition.
• How do plants obtain carbon dioxide?
• Role of guard cells.
• Stomata and its function with the help of diagram.
• Main events of photosynthesis.
• Importance of nitrogen.
• Where does photosynthesis takes place. Explain.
• Explain herbivores, carnivores and omnivores?
• Sun is the ultimate source of energy?
• Different stages of feeding/nutrition in amoeba.
• How paramecium eats food?
• Importance of Peristaltic movement.
• Name the gland which secretes HCl, digesting enzyme and mucus
• Human digestive system. With example.
• The initial starch in the plants has to be removed before we use them for photosynthesis, why?
• Function of salivary glands.
• Reason for gastric juice being acidic in nature.
• Where does protein digestion begins?
• Explain protein digestive enzyme pepsin is active only in the presence of an acid?
• Role of mucus and HCl.
• Herbivores have longer small intestine than carnivores. Explain.
• Site for the complete digestion of carbohydrate, protein and fats.
• Write about the emulsification of fat and mention the role of bile salt.
• Name the enzymes present in the pancreatic juice.
• Intestinal juice secreted by small intestine or large intestine.
• The juice / enzyme responsible for the final conversion of protein into amino acids , complex carbohydrate into glucose and fats into fatty acid and glycerol.
• Mention three functions of villi.
• Place where glucose is break down into pyruvate.
• Breakdown of glucose by various pathways.
• Name of the structure where exchange of gases takes place.
• In animal where the body size is small, diffusion pressure is sufficient to distribute the oxygen through the body but when body size is large how this phenomenon get takes place.
• Which is more soluble in water, oxygen or CO2?
• What is double circulation?
• Values of systolic and diastolic pressure.
• Two functions of lymph.
• What is the unit of excretion?
• Which muscle regulate the exit of food.
• Phagocytosis and its role.
• Dental plaque and how is it harmful.
• Cellular respiration and its process.
• Why respiration is called a complex process.
• All information regarding ATP.
• How can yeast live without oxygen?
• What do you understand by lenticels?
• Why is the rate of breathing much faster in aquatic animal than terrestrial animals?
• Why is diffusion insufficient to meet the need of large multicellular organisms?
• What will happen if carbon mono oxide combines with hemoglobin?
• Reason for moist skin of earthworm.
• What do you understand by trachea? What role does it play?
• Bronchioles and its function.
• Availability of large surface maximized the gases? Explain.
• Land plant dies if water get logged for a longer time period, explain.
• Process of air cleaning while passing through nasal passage.
• The two openings of the pharynx, one leading to trachea and the other leading to esophagus, lie very close to each other. Yet the swallow food does not enter into our trachea. Why?
• Explain- Xylem vessel runs like long a long drainpipe through the plant.
• Structure of xylem vessel and tracheid.
• How is food transported in plants?
• Structure of phloem.
• Difference between plasma, RBC and WBC. Functions of blood.
• Role of platelets in dengue fever.
• Diagram of heart and blood circulation in human body.
• Reason for heartbeat being nonstop at all the time?
• Systolic pressure and diastolic pressure.
• Vessels collect the blood from the body and distribute the blood to the body.
• Lymph is another medium of circulation in human body? Agree or not.
• Plant store waste products in their body too?
• Bowman’s capsule and its function.
• Some people use dialysis machine while others not. What is the reason behind it.

#7 CONTROL AND COORDINATION

• How do living organisms show response to stimuli?
• Reaction of stimuli is a characteristic property of living organisms. Explain.
• It usually takes lot of time to observe the effect of a stimulus on plants. Explain.
• Difference between dormancy and breaking of dormancy.
• Four major types of plant hormones and their functions.
• How does tropism helps in movement?
• Why does the stem of a plant bend to one direction?
• Explain the bending of plant root away from light by the action of auxin hormones.
• Give an example of chemotropism? With the help of diagram.
• Roots can grow against the law of gravity. When does this happen?
• Definition and Function of thigmotropism.
• Why do followers open their petals in morning and close them in evening
• Scientific terms for-
  Bending of shoot towards sunlight
  Growing of root towards the earth
  Growth of a pollen tube towards ovule
  Bending of root towards water
• Winding of tendril around a support
• Receptor and its role.
• Function of Human nervous system.
• Explain the function of electrical impulses.
• Draw the diagram of neuron and explain its function.
• How are messages transferred from one neuron to another?
• Gap between two neurons.
• Explain the types of peripheral nervous system.
• In a reflex action, we are unaware that anything is going to happen to us. Explain.
• Diagram of reflex arc with its details.
• How effectors cause action.
• Self governing nervous system and its function.
• Function of central nervous system and its way of functioning.
• Brain is the highest coordinating centre in the body. Explain

#8 REPRODUCTION

• Examples of spore formation are ………………….
• Female part of the flower is called ………………..
• After fertilization ovary develops into ……………..
• Female sex hormone is ……………………..
• Foetus obtains its food through mother by ………………..
• What is the difference between fission and fragmentation?
• What is implantation?
• What is regeneration? Define with example?
• Name two examples of sexually transmitted diseases with their causing agent.
• Write the difference between self-pollination and cross pollination.
• What is tissue culture write its advantages?
• Describe fertilization in flower.
• Write different methods through which pregnancy can be controlled?
• What are different male reproductive organs? Describe the functions of each.
• What is vegetative propagation? Describe one natural method of vegetative propagation with example?
• Draw a well labelled diagram of female reproductive system.
• Differentiate between zygote, embryo and foetus?
• How seed is germinated?

#9 HEREDITY & EVOLUTION

• Do all variations in a particular species have equal chances of survival in an environment?
• Give scientific terms for;
  • the similarities with parents present in an offspring.
  • the differences with parents present in an offspring.
• When is a recessive trait capable of expressing itself?write its expression with respect to height of plant(genotype).
• When a pesticide is sprayed on a population of insects,all insects do not get killed but few of them survive. Give reason.
• In a mendelian cross,tall plants and purple flowers were crossed with dwarf plant and white flowers.How would you denote————
  • a)the genotype of the two parents.
  • the genotype and phenotype of F1 progeny.
  • the results obtained by selfing F1 progeny to get F2 progeny. Give the ratio obtained in F2 generation.
• Who is known as father of genetics?
• Write the scientific name of the plant on which Mendel carried out his experiment.
• How many chromosomes are present in human beings?
• What is the genetic material?what is its importance?
• What are recessive genes?
• What are dominant genes?
• Name the cells which possess half the number of chromosomes in human beings? (hint-germ or reproductive cells)
• State the advantages of sexual reproduction?
• Name any two contrasting characters noticed by Mendel in the garden pea plants.
• State the ratio of plants produced in the monohybrid cross in the F1 and F2 generation?
• Where are genes located? What is the chemicals nature of genes?
• How is the sex of a newborn child determined inhumans?
• Why did Mendel chose pea plant for his experiment?
• Give reasons why acquired characters are not inherited.
• What are the functions played by DNA?

#10 LIGHT- REFLECTION & REFRACTION

• Where will the image be formed when the object is placed between the focus and the pole (infinity, pole) of the convex mirror?
• With respect to air the refractive index of ice and that of rock salts are 1.31 and 1.54 respectively. Calculate the refractive index of rock salt with respect to ice.
• With respect to air the refractive index of water and that of benzene are 1.33 and 1.50 respectively. Calculate the refractive index of benzene with respect to water.
• Wavelength of radiation 850nm falls on a surface. Will this surface be visible or not? Explain.
• A convex mirror used on a truck has 3m radius of curvature. If a bus is located at 5m from this mirror. Find the position, nature and size of the image.
• What is the condition under which motion pictures can be clearly seen?
• What is accommodation? What is the maximum variation in power of accommodation in human eye?
• An object of size 5cm is placed at a distance of 25cm from the pole of a concave mirror of radius of curvature 30cm. Cal
• An object of size 3cm is placed at a distance of 15cm from a convex lens of focal length 10cm. Calculate the distance and size of the image so formed. What will be the nature of image?
• Light enters from air to glass plate having refractive index 1.50. What is the speed of light if the speed of light in air is m/s?
• What is dispersion? Which color of light deviates more on passing through a prism? When two prisms are placed together with one inverted and white light is passed, what will be the result?
• What are the conditions for the formation of rainbow?
• Why do blue and yellow pigments give green color on mixing? Explain as clearly as possible and support your answer with a diagram.
• What are the values for the angle of incidence and angle of reflection for normal incidence?
• What is the relation between the critical angle and the refractive index for a medium?
• Explain the phenomenon of mirage in deserts and looming in the seas? Support your answer with diagrams. Why does a diamond glitter more? Which phenomenon does optic fiber work upon?
• An object is placed 20cm in front of mirrors M1 and M2 separately and image is found to be formed at a distance of 15cm in front of it in case of M1 and behind it in case of M2. Find the focal length and kind of mirror in each case.
• Give two differences between real and virtual images.
• Derive mirror formula for a concave mirror.
• Derive lens formula for a convex lens.
• What is the critical angle of incidence?

#11 THE HUMAN EYE & THE COLOURFUL WORLD

• Function of lens in human eye.
• Draw a labeled diagram of a human eye and explain its functions?
• What is the function of rods and cones?
• Accommodation of eye and the least distance of distinct vision.
• When entering a darkened cinema hall from bright light, we cannot see at first but gradually the vision becomes visible. Why?
• Define myopia, hypermetropia and presbyopia?
• By just looking at the spectacles how can a person judge whether the spectacles is for long-sighted or short-sighted?
• Draw a labeled diagram to show the defect of myopia and hypermetropia?
• An old person finds difficulty in watching number board of a far bus? What defect is the person suffering from? How can it be corrected?
• Explain the process of refraction of prism with the help of a labeled diagram?
• Relation between the refraction through glass slab and through a prism?
• Why do we get 7 colors? Explain
• Which refracted most: Red light or violet light? Explain why?
• Interconnect the process of rainbow with that of dispersion through prism.
• The process of stars twinkling at night and its displacement from its actual position when viewed from earth.
• Reason for advanced sunrise and delayed sunset.
• Deep water is blue in color? Reason.
• Explain the process of blue color of sky and reddening of sun during sunset?
• Tyndall effect with diagram
• Why is danger signal board red in colour?
• Sun appears white at noon and red during sunset at the horizon. Why?
• What causes the scattering of blue component of sunlight in the atmosphere?

#12 ELECTRICITY

• What do you mean by static electricity and current electricity?
• SI unit of electric charge and current
• Basic differences between conductor and insulator
• What are free electrons?
• Electric potential in words and formula along with potential energy and its SI unit
• How much work is done in moving a charge of 2 coulombs from a point at 118 volts to a point at 128 volts?
• Device used to measure p.d?
• Relation between potential difference, work done, and charge moved?
• The atoms of copper contain electrons and the atoms of rubber also contain electrons? Why does copper conducts electricity?
• What is Ammeter? And why should it have low resistance? Explain with diagram
• An electric bulb draws a current of 0.25 A for 20 minutes. Calculate the amount of electric charge that flows through the circuit
• Process of flowing current in a wire
• Electric circuit and different symbols of electric components?
• Potential difference between two points of a wire carrying 2 ampere current is 0.1 volt. Calculate the resistance between these points.
• Distinguish between good conductor, resistors and insulators. Give example.
• Why do electricians wear gloves while working with electricity?
• What is resistivity of a substance? And on what factors a resistivity of a substance depends?
• A copper wire of length 2m and area of cross- section 1.7 x 10-6 m2 has a resistance of 2 x 10-2 ohms. Calculate the resistivity of copper.
• Write down an expression for the resistance of a metallic wire in terms of the resistivity?
• Ohm’s law and it’s application
• Resistivity of a conductor depends on
• A resistance of 6 ohms is connected in series with another resistance of 4 ohms. A potential difference of 20 volts is applied across the combination. Calculate the current through the circuit and potential difference across the 6 ohm resistance.
• What is meant by the “series combination” and “parallel combination” of resistances? In which case the resultant resistance is:
  i. Less
  ii. More than either of the individual resistances?
• An electric bulb of resistance 20 ohms and a resistance wire of 4 ohms are connected in series with a 6 V battery. Draw the circuit diagram and calculate:
  a. Total resistance of the circuit
  b. Current through the circuit
  c. Potential difference across the electric bulb
  d. Potential difference across the resistance wire
• Disadvantage of series circuits for domestic wiring
• Advantages of parallel circuit in domestic wiring
• Why lights are in house wired in series
• How to calculate electric power
• What is the relation between kilowatt-hour and joule?
• What do you understand by watt? Write down an equation linking watts, volts, amperes
• Heating effect of current and different formula to calculate the heat energy
• Joule’s law of heating
• All appliances which run on electricity do not convert all the electric energy into heat. Explain
• Factors on which the heat produced by an electric current depends?
• Why is argon or nitrogen filled in electric bulb instead of air?
  SI unit of
  I. Electric charge
  II. Potential difference
  III. Electric current
  IV. Resistance
  V. Power
  VI. Electric energy

#13 MAGNETIC EFFECTS OF CURRENT

• Magnetic field. How can the direction of field lines at a place be determined?
• Magnetic field lines do not intersect each other. Explain.
• Properties of the Magnetic field lines
• When an electric current is passed through any wire, a magnetic field is produced around it. then why an electric iron connecting cables does not attract nearby iron objects when electric current is switched on though it?
• A freely suspended magnet always point in north-south direction. Explain
• State and explain the clock face rule for determining the polarities of a circular wire carrying current.
• What are the factor affecting the strength of an electromagnet.
• Difference between a bar magnet and electromagnet
• What is solenoid? Diagram for magnetic field due to current carrying solenoid. Uses of solenoid.
• Difference between bar magnet and company Magnet
• Clock face rule. The process of determining the polarities of a circular wire carrying current through clock face rule.
• What Type of core should be put inside a current carrying solenoid to make an electromagnet?
• As magnetic field has Magnitude as well as direction. Explain.
• No two magnetic field lines are found to cross each other. Explain
• Importance of MRI for human body
• How to locate a current wire concealed in a wall.
• Explain- No force acts on a current carrying conductor when it is parallel to the magnetic field.
• Explain Flemings’ left hand rule for the direction of force.
• On what principal does motor work?
• With diagram the working of electric motor?
• How will you find the direction if a current carrying conductor is placed in a perpendicular field.
• Special features of commercial electric motor.
• Example of electromagnetic induction
• How can we increase the magnitude of current induced in the coil.
• What is electric generator and its principal.
• Two circular coils A and B are placed close to each other. If the current in coil A is change, will some current be induced in coil B? Give reason.
• AC generator and its diagram, explain its construction and working of AC generator
• Why the direction of induced current in the coil of an AC generator changes after direction showing the production of the coil.
• What normally drives the alternators in a thermal power station? What fuels can be used to heat water in the boiler?
• A circuit has fuse of a 5 A. what is the maximum number of 100 W (220 V) bulbs that can be safely used in the circuit?
• How is earthing of electric appliances done?
• What type of electric fuse is used in electrical appliances like stereos? Explain with diagram.
• Difference between overloading and short- circuiting as used in domestic circuits.
• An air-conditioner of 3.2 kW power rating is connected to a domestic electric circuit having a current rating of 10 A. the voltage of power supply is 220 V. what will happen when this air- conditioner is switched on? Explain your answer.

#14 SOURCES OF ENERGY

• Why is charcoal better than wood as a fuel ?
• How can we overcome energy crisis?
• A concave reflector increases the temperature that can be obtained inside a solar cooker. Give reason.
• Why is natural gas non renewable source of energy
• Explain the working of nuclear reactor?
• What are the advantages and disadvantages of thermal power plants?
• What is a solar cell panel? Mention two applications of it?

#15 OUR ENVIRONMENT

• Define Ecology
• What is the scope of Ecology Research?
• Define Ecosystem.
• Is garden an example of Ecosystem?
• Give examples of natural ecosystems.
• Give examples of human made (artificial )ecosystems.
• Name different abiotic factors that affect the ecosystem.
• What do you mean by biogeochemical cycle? Name examples of biogeochemical cycles exist in ecosystem.
• What do you mean by biosphere?
• Define food chain.
• What are trophic levels?
• Define Detritivores.
• Explain energy relationship with trophic levels.
• Explicate the principle of food web.
• Define biological magnification.
• Explain Ozone depletion and its impact on our environment?

#16 CONSERVATION OF NATURAL RESOURCES

• Definition of sustainable development?
• Reasons for managing our resources.
• What do you mean by stakeholders and how many types of stakeholders are there?
• Silviculture and its advantages.
• An assay on conservation of wildlife.
• What are measures to be taken for the conservation of wildlife?
• Rain is very important source of water. Explain.
• Reason to built DAM with advantages and disadvantages.
• Name of the DAMs and river associated with them.
• Rain water harvesting in urban areas with the help of diagram.
• The pH of a river water sample as measured by pH paper is found to be 6. What does it tell us about water?
• Describe the khadin system of rainwater harvesting practiced in Rajasthan.
• What are three Rules to save environment? Explain with one example.
• How can the participation of local people lead to the efficient management of forest? Give example.
• Name the two fossil fuels.
• How rainwater harvesting is done from open space around the buildings in city areas.
• Write the short note on “Hug the Tree Movement”.
• Suggest some approaches towards the conservation of forest.

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