CBSE Class 10 Science Previous Year Question Paper 2018
SECTION - A
1. Write the energy conversion that takes place in a hydropower plant.
Ans: Potential energy of water stored in a dam is converted into kinetic energy of the falling water. The water falls on the turbine, so kinetic energy of the flowing water is converted into the kinetic energy of the armature of the generator connected to the turbine. Then kinetic energy is converted into the electrical energy known as hydro-electricity.
2. A Mendelian experiment consisted of breeding pea plants bearing violet flowers with pea plants bearing white flowers. What will be the result in F1 progeny?
Ans: In Mendelian experiment, breeding of pea plants bearing violet flowers with pea plant bearing white flower leads to production of all violet coloured flowers (F1 progeny plants). The plants bearing violet colour of the flower is dominant over white coloured flower in pea plant.
3. (a) Name one gustatory receptor and one olfactory receptor present in human beings.
(b) Write a and b in the given flow chart of neuron through which information travels as an electrical impulse.
Dendrite → a → b → End point of Neuron
(b) Write a and b in the given flow chart of neuron through which information travels as an electrical impulse.
Dendrite → a → b → End point of Neuron
Ans: (a) Gustatory receptors – Tongue; Olfactory receptors – Nose.
(b) Dendrite → Cyton → Axon → End point of Neuron.
(b) Dendrite → Cyton → Axon → End point of Neuron.
4. If the image formed by a spherical mirror for all positions of the object placed in front of it is always erect and diminished, what type of mirror is it? Draw a labelled ray diagram to support your answer.
Ans: To get erect and diminished image mirror used is convex mirror. [Diagram required showing virtual, erect, diminished image formed by convex mirror].
5. A compound ‘X’ on heating with excess conc. sulphuric acid at 443 K gives an unsaturated compound ‘Y’. ‘X’ also reacts with sodium metal to evolve a colourless gas ‘Z’. Identify ‘X’, ‘Y’ and ‘Z’. Write the equation of the chemical reaction of formation of ‘Y’ and also Write the role of sulphuric acid in the reaction.
Ans:
Compound ‘X’ is Ethanol (C2H5OH).
Compound ‘Y’ is Ethene (C2H4).
Gas ‘Z’ is Hydrogen (H2).
Reaction of formation of Y: CH3-CH2-OH &xrightarrow{Conc. H2SO4, 443 K} CH2=CH2 + H2O
Role of Sulphuric acid: Concentrated H2SO4 acts as a dehydrating agent.
Compound ‘Y’ is Ethene (C2H4).
Gas ‘Z’ is Hydrogen (H2).
Reaction of formation of Y: CH3-CH2-OH &xrightarrow{Conc. H2SO4, 443 K} CH2=CH2 + H2O
Role of Sulphuric acid: Concentrated H2SO4 acts as a dehydrating agent.
6. State the laws of refraction of light. Explain the term ‘absolute refractive index of a medium’ and write an expression to relate it with the speed of light in vacuum.
Ans:
Laws of Refraction:
1. The incident ray, the normal to the transparent surface at the point of incidence and the refracted ray, all lie in one and the same plane.
2. The ratio of sine of the incidence angle (i) to the sine of the refracted angle (r) is constant for a given pair of media (Snell's Law): sin i / sin r = constant (n).
Absolute Refractive Index: Absolute refractive index of a medium is defined as the ratio of the speed of light in vacuum or air to the speed of light in the medium. It is denoted by n.
Expression: n = c / v (where c is speed of light in air/vacuum and v is speed of light in the medium).
1. The incident ray, the normal to the transparent surface at the point of incidence and the refracted ray, all lie in one and the same plane.
2. The ratio of sine of the incidence angle (i) to the sine of the refracted angle (r) is constant for a given pair of media (Snell's Law): sin i / sin r = constant (n).
Absolute Refractive Index: Absolute refractive index of a medium is defined as the ratio of the speed of light in vacuum or air to the speed of light in the medium. It is denoted by n.
Expression: n = c / v (where c is speed of light in air/vacuum and v is speed of light in the medium).
OR
What is meant by power of a lens? Write its SI unit. A student uses a lens of focal length 40 cm and another of –20 cm. Write the nature and power of each lens.
Ans: Power of a lens is the reciprocal of its focal length in meters. P = 1/f. SI unit is Dioptre (D).
Lens 1: f = 40 cm = 0.4 m. Power P = 1/0.4 = +2.5 D. Nature: Convex lens.
Lens 2: f = -20 cm = -0.2 m. Power P = 1/-0.2 = -5 D. Nature: Concave lens.
Lens 1: f = 40 cm = 0.4 m. Power P = 1/0.4 = +2.5 D. Nature: Convex lens.
Lens 2: f = -20 cm = -0.2 m. Power P = 1/-0.2 = -5 D. Nature: Concave lens.
7. Write one main difference between asexual and sexual mode of reproduction. Which species is likely to have comparatively better chances of survival - the one reproducing asexually or the one reproducing sexually? Give reason to justify your answer.
Ans: Asexual reproduction involves a single individual producing a new generation, whereas sexual reproduction involves two individuals (male and female parents). Sexually reproducing species are likely to have better chances of survival because sexual reproduction involves the combination of DNA from two different gametes, leading to variations. Variations help individuals adapt to changing environments and aid in the survival of the species.
8. Show how would you join three resistors, each of resistance 9 Ω so that the equivalent resistance of the combination is (i) 13.5 Ω (ii) 6 Ω?
Ans:
(i) To get 13.5 Ω: Connect two 9 Ω resistors in parallel and one in series.
Calculation: Parallel combination = (9 × 9) / (9 + 9) = 4.5 Ω. Total = 4.5 + 9 = 13.5 Ω.
(ii) To get 6 Ω: Connect two 9 Ω resistors in series, and then connect this combination in parallel with the third 9 Ω resistor.
Calculation: Series combination = 9 + 9 = 18 Ω. Parallel with 9 Ω: (18 × 9) / (18 + 9) = 162 / 27 = 6 Ω.
Calculation: Parallel combination = (9 × 9) / (9 + 9) = 4.5 Ω. Total = 4.5 + 9 = 13.5 Ω.
(ii) To get 6 Ω: Connect two 9 Ω resistors in series, and then connect this combination in parallel with the third 9 Ω resistor.
Calculation: Series combination = 9 + 9 = 18 Ω. Parallel with 9 Ω: (18 × 9) / (18 + 9) = 162 / 27 = 6 Ω.
OR
(a) Write Joule’s law of heating.
(b) Two lamps, one rated 100 W; 220 V, and the other 60 W; 220 V, are connected in parallel to electric mains supply. Find the current drawn by two bulbs from the line, if the supply voltage is 220 V.
(b) Two lamps, one rated 100 W; 220 V, and the other 60 W; 220 V, are connected in parallel to electric mains supply. Find the current drawn by two bulbs from the line, if the supply voltage is 220 V.
Ans: (a) Joule’s law of heating states that heat produced in a resistor is directly proportional to the square of current (I2), resistance (R), and time (t). Formula: H = I2Rt.
(b) Current for 100 W bulb: I1 = P/V = 100/220 = 0.45 A.
Current for 60 W bulb: I2 = P/V = 60/220 = 0.27 A.
Total Current: I = I1 + I2 = 0.45 + 0.27 = 0.72 A (approx).
(b) Current for 100 W bulb: I1 = P/V = 100/220 = 0.45 A.
Current for 60 W bulb: I2 = P/V = 60/220 = 0.27 A.
Total Current: I = I1 + I2 = 0.45 + 0.27 = 0.72 A (approx).
9. Name the hormones secreted by the following endocrine glands and specify one function of each:
(a) Thyroid (b) Pituitary (c) Pancreas
(a) Thyroid (b) Pituitary (c) Pancreas
Ans:
(a) Thyroid: Secretes Thyroxin. Function: Regulates carbohydrate, protein, and fat metabolism for growth.
(b) Pituitary: Secretes Growth Hormone. Function: Regulates growth and development of the body.
(c) Pancreas: Secretes Insulin. Function: Regulates blood sugar levels.
(b) Pituitary: Secretes Growth Hormone. Function: Regulates growth and development of the body.
(c) Pancreas: Secretes Insulin. Function: Regulates blood sugar levels.
10. 2 mL of sodium hydroxide solution is added to a few pieces of granulated zinc metal taken in a test tube. When the contents are warmed, a gas evolves which is bubbled through a soap solution before testing. Write the equation of the chemical reaction involved and the test to detect the gas. Name the gas which will be evolved when the same metal reacts with dilute solution of a strong acid.
Ans:
Reaction: 2NaOH + Zn → Na2ZnO2 (Sodium Zincate) + H2.
Test: The gas burns with a "pop" sound when a burning matchstick is brought near it.
Reaction with strong acid (HCl): Zn + 2HCl → ZnCl2 + H2. The gas evolved is Hydrogen (H2).
Test: The gas burns with a "pop" sound when a burning matchstick is brought near it.
Reaction with strong acid (HCl): Zn + 2HCl → ZnCl2 + H2. The gas evolved is Hydrogen (H2).
OR
The pH of a salt used to make tasty and crispy pakoras is 14. Identify the salt and write a chemical equation for its formation. List its two uses.
Ans:
Note: The question states pH is 14, but the salt used for crispy pakoras is typically Baking Soda (NaHCO3), which is a mild base (pH ~8-9). The provided solution identifies the salt as NaHCO3 despite the pH 14 statement.
Salt: Sodium Hydrogen Carbonate (NaHCO3).
Formation: Na2CO3 + H2O + CO2 → 2NaHCO3.
Uses: (1) As an antacid in medicine. (2) Used in baking powder for cakes.
Salt: Sodium Hydrogen Carbonate (NaHCO3).
Formation: Na2CO3 + H2O + CO2 → 2NaHCO3.
Uses: (1) As an antacid in medicine. (2) Used in baking powder for cakes.
11. (a) Why are most carbon compounds poor conductors of electricity?
(b) Write the name and structure of a saturated compound in which the carbon atoms are arranged in a ring. Give the number of single bonds present in this compound.
(b) Write the name and structure of a saturated compound in which the carbon atoms are arranged in a ring. Give the number of single bonds present in this compound.
Ans:
(a) Carbon compounds form covalent bonds, which involve the sharing of electrons. They do not dissociate into ions, hence they are poor conductors of electricity.
(b) Name: Cyclohexane (C6H12). Structure: A hexagonal ring of 6 Carbon atoms, each attached to 2 Hydrogen atoms. Number of single bonds: 18 (6 C-C bonds + 12 C-H bonds).
(b) Name: Cyclohexane (C6H12). Structure: A hexagonal ring of 6 Carbon atoms, each attached to 2 Hydrogen atoms. Number of single bonds: 18 (6 C-C bonds + 12 C-H bonds).
12. Decomposition reactions require energy either in the form of heat or light or electricity for breaking down the reactants. Write one equation each for decomposition reactions where energy is supplied in the form of heat, light and electricity.
Ans:
Heat (Thermal decomposition): 2Pb(NO3)2(s) &xrightarrow{\Delta} 2PbO(s) + 4NO2(g) + O2(g)
Light (Photochemical decomposition): 2AgCl(s) &xrightarrow{Sunlight} 2Ag(s) + Cl2(g)
Electricity (Electrolytic decomposition): 2NaCl(l) &xrightarrow{Electricity} 2Na(s) + Cl2(g) (or Water electrolysis).
Light (Photochemical decomposition): 2AgCl(s) &xrightarrow{Sunlight} 2Ag(s) + Cl2(g)
Electricity (Electrolytic decomposition): 2NaCl(l) &xrightarrow{Electricity} 2Na(s) + Cl2(g) (or Water electrolysis).
13. What is a dam? Why do we seek to build large dams? While building large dams, which three main problems should particularly be addressed to maintain peace among local people? Mention them.
Ans: A dam is a barrier constructed to hold back water and raise its level forming a reservoir. Large dams are built primarily to generate electricity and ensure water supply.
Problems to address:
1. Rehabilitation of displaced people.
2. Destruction of large ecosystems/deforestation.
3. Submersion of agricultural land.
14. (Value Based Question on Garbage Management) - (a) Suggest two measures to manage the garbage we produce. (b) As an individual, what can we do to generate the least garbage? (c) List two values the teacher instilled in his students.
Ans:
(a) (i) Segregate wet and dry garbage. (ii) Proper disposal in municipal bins.
(b) (i) Cook only required food to avoid waste. (ii) Reuse items and give organic waste to animals/compost.
(c) Environmental consciousness and social responsibility.
(b) (i) Cook only required food to avoid waste. (ii) Reuse items and give organic waste to animals/compost.
(c) Environmental consciousness and social responsibility.
15. (a) List the factors on which the resistance of a conductor in the shape of a wire depends.
(b) Why are metals good conductors of electricity whereas glass is a bad conductor of electricity? Give reason.
(c) Why are alloys commonly used in electrical heating devices? Give reason.
(b) Why are metals good conductors of electricity whereas glass is a bad conductor of electricity? Give reason.
(c) Why are alloys commonly used in electrical heating devices? Give reason.
Ans:
(a) Resistance depends on: (i) Length of wire (R ∝ l), (ii) Area of cross-section (R ∝ 1/A), (iii) Nature of material, (iv) Temperature.
(b) Metals have free electrons to carry current, while glass does not have free electrons.
(c) Alloys have higher resistivity than pure metals and do not oxidize (burn) readily at high temperatures.
(b) Metals have free electrons to carry current, while glass does not have free electrons.
(c) Alloys have higher resistivity than pure metals and do not oxidize (burn) readily at high temperatures.
16. (a) State Fleming’s left hand rule.
(b) Write the principle of working of an electric motor.
(c) Explain the function of the following parts of an electric motor: (i) Armature (ii) Brushes (iii) Split ring
(b) Write the principle of working of an electric motor.
(c) Explain the function of the following parts of an electric motor: (i) Armature (ii) Brushes (iii) Split ring
Ans:
(a) Fleming's Left Hand Rule: Hold the forefinger, center finger, and thumb of your left hand at right angles. If the forefinger points in the direction of the magnetic field and the center finger in the direction of the current, then the thumb points in the direction of the force (motion).
(b) Principle: A current-carrying conductor placed perpendicular to a magnetic field experiences a force.
(c) (i) Armature: A coil of insulated copper wire on a soft iron core that rotates. (ii) Brushes: Carbon brushes act as sliding contacts to conduct current from the battery to the rotating coil. (iii) Split ring (Commutator): Reverses the direction of current in the coil every half rotation to maintain unidirectional torque.
(b) Principle: A current-carrying conductor placed perpendicular to a magnetic field experiences a force.
(c) (i) Armature: A coil of insulated copper wire on a soft iron core that rotates. (ii) Brushes: Carbon brushes act as sliding contacts to conduct current from the battery to the rotating coil. (iii) Split ring (Commutator): Reverses the direction of current in the coil every half rotation to maintain unidirectional torque.
17. (a) Write the function of following parts in human female reproductive system: (i) Ovary (ii) Oviduct (iii) Uterus.
(b) Describe in brief the structure and function of placenta.
(b) Describe in brief the structure and function of placenta.
Ans:
(a) (i) Ovary: Production of eggs and secretion of hormones (estrogen/progesterone). (ii) Oviduct (Fallopian tube): Site of fertilization; carries egg to uterus. (iii) Uterus: Site of implantation and nourishment of the embryo.
(b) Placenta: A disc-like structure embedded in the uterine wall. It contains villi on the embryo's side. Function: Provides nourishment (glucose, oxygen) to the embryo from the mother's blood and removes waste products from the embryo.
(b) Placenta: A disc-like structure embedded in the uterine wall. It contains villi on the embryo's side. Function: Provides nourishment (glucose, oxygen) to the embryo from the mother's blood and removes waste products from the embryo.
18. (a) Write the steps involved in the extraction of pure metals in the middle of the activity series from their carbonate ores.
(b) 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.
(b) 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.
Ans:
(a) (i) Concentration of ore. (ii) Calcination (heating in limited air) to convert carbonate to oxide: ZnCO3 → ZnO + CO2. (iii) Reduction of oxide with carbon: ZnO + C → Zn + CO. (iv) Purification.
(b) Copper extraction from sulphide ore (Copper Glance Cu2S): (1) Roasting: 2Cu2S + 3O2 → 2Cu2O + 2SO2. (2) Reduction (Auto-reduction): 2Cu2O + Cu2S → 6Cu + SO2. (3) Electrolytic refining diagram required.
(b) Copper extraction from sulphide ore (Copper Glance Cu2S): (1) Roasting: 2Cu2S + 3O2 → 2Cu2O + 2SO2. (2) Reduction (Auto-reduction): 2Cu2O + Cu2S → 6Cu + SO2. (3) Electrolytic refining diagram required.
19. (a) Mention any two components of blood.
(b) Trace the movement of oxygenated blood in the body.
(c) Write the function of valves present in between atria and ventricles.
(d) Write one structural difference between the composition of artery and veins.
(b) Trace the movement of oxygenated blood in the body.
(c) Write the function of valves present in between atria and ventricles.
(d) Write one structural difference between the composition of artery and veins.
Ans:
(a) Plasma, Blood cells (RBCs, WBCs, Platelets).
(b) Pulmonary veins → Left Atrium → Left Ventricle → Aorta → Body Parts.
(c) Valves prevent the backflow of blood.
(d) Arteries have thick, elastic walls; Veins have thin walls.
(b) Pulmonary veins → Left Atrium → Left Ventricle → Aorta → Body Parts.
(c) Valves prevent the backflow of blood.
(d) Arteries have thick, elastic walls; Veins have thin walls.
OR
(a) Define excretion.
(b) Name the basic filtration unit present in the kidney.
(c) Draw excretory system in human beings and label...
(b) Name the basic filtration unit present in the kidney.
(c) Draw excretory system in human beings and label...
Ans:
(a) Excretion is the biological process of removal of harmful metabolic wastes from the body.
(b) Nephron.
(c) Diagram required labeling: Kidney (forms urine), Ureter (tube collecting urine), Urinary Bladder (stores urine).
(b) Nephron.
(c) Diagram required labeling: Kidney (forms urine), Ureter (tube collecting urine), Urinary Bladder (stores urine).
20. (a) The modern periodic table has been evolved through the early attempts of Dobereiner, Newland and Mendeleev. List one advantage and one limitation of all the three attempts.
(b) Name the scientist who first of all showed that atomic number of an element is a more fundamental property than its atomic mass.
(c) State Modern periodic law.
(b) Name the scientist who first of all showed that atomic number of an element is a more fundamental property than its atomic mass.
(c) State Modern periodic law.
Ans:
(a) Dobereiner: Adv - Recognized grouping by properties (triads). Lim - Could not identify many triads.
Newland: Adv - Related properties to atomic mass (Law of Octaves). Lim - Valid only up to Calcium.
Mendeleev: Adv - Predicted existence of undiscovered elements. Lim - Position of isotopes/Hydrogen was uncertain.
(b) Henry Moseley.
(c) Modern Periodic Law: The physical and chemical properties of elements are periodic functions of their atomic numbers.
Newland: Adv - Related properties to atomic mass (Law of Octaves). Lim - Valid only up to Calcium.
Mendeleev: Adv - Predicted existence of undiscovered elements. Lim - Position of isotopes/Hydrogen was uncertain.
(b) Henry Moseley.
(c) Modern Periodic Law: The physical and chemical properties of elements are periodic functions of their atomic numbers.
21. (a) A student is unable to see clearly the words written on the black board placed at a distance of approximately 3 m from him. Name the defect of vision the boy is suffering from. State the possible causes of this defect and explain the method of correcting it.
(b) Why do stars twinkle? Explain.
(b) Why do stars twinkle? Explain.
Ans:
(a) Myopia (Near-sightedness). Causes: Elongation of eyeball or excessive curvature of eye lens. Correction: Using a concave lens of suitable focal length.
(b) Stars twinkle due to atmospheric refraction. Starlight passes through changing layers of atmospheric density, causing the apparent position of the star to fluctuate and the intensity of light reaching the eye to vary.
(b) Stars twinkle due to atmospheric refraction. Starlight passes through changing layers of atmospheric density, causing the apparent position of the star to fluctuate and the intensity of light reaching the eye to vary.
OR
(a) Write the function of: (i) Cornea (ii) Iris (iii) Crystalline lens (iv) Ciliary muscles.
(b) Why does the sun appear reddish early in the morning? Will this phenomenon be observed by an astronaut on the Moon?
(b) Why does the sun appear reddish early in the morning? Will this phenomenon be observed by an astronaut on the Moon?
Ans:
(a) (i) Cornea: Allows light to enter. (ii) Iris: Controls pupil size. (iii) Lens: Focuses image on retina. (iv) Ciliary muscles: Adjust focal length of lens.
(b) At sunrise, sunlight travels a longer distance through the atmosphere. Shorter wavelengths (blue) scatter away, leaving longer wavelengths (red) to reach the eye. Astronauts will not observe this as there is no atmosphere on the Moon to scatter light.
(b) At sunrise, sunlight travels a longer distance through the atmosphere. Shorter wavelengths (blue) scatter away, leaving longer wavelengths (red) to reach the eye. Astronauts will not observe this as there is no atmosphere on the Moon to scatter light.
SECTION - B
22. Name the process by which an amoeba reproduces. Draw the various stages of its reproduction in a proper sequence.
Ans: Amoeba reproduces by Binary Fission. [Diagram required showing nucleus division followed by cytoplasm division].
OR
Draw diagrams showing budding in yeast.
Ans: [Diagram required showing bud formation and chain of cells].
23. An object of height 4.0 cm is placed at a distance of 30 cm from the optical centre ‘O’ of a convex lens of focal length 20 cm. Draw a ray diagram to find the position and size of the image formed. Also find the approximate ratio of size of the image to the size of the object.
Ans:
Given: u = -30 cm, f = +20 cm, ho = 4 cm.
Lens formula: 1/v - 1/u = 1/f ⇒ 1/v = 1/20 + 1/-30 = (3-2)/60 = 1/60. So, v = 60 cm.
Magnification m = v/u = 60/-30 = -2.
Image height hi = m × ho = -2 × 4 = -8 cm.
Ratio of size of image to object: |hi|/ho = 8/4 = 2.
Lens formula: 1/v - 1/u = 1/f ⇒ 1/v = 1/20 + 1/-30 = (3-2)/60 = 1/60. So, v = 60 cm.
Magnification m = v/u = 60/-30 = -2.
Image height hi = m × ho = -2 × 4 = -8 cm.
Ratio of size of image to object: |hi|/ho = 8/4 = 2.
24. A student added few pieces of aluminium metal to two test tubes A and B containing aqueous solutions of iron sulphate and copper sulphate. In the second part of her experiment, she added iron metal to another test tubes C and D containing aqueous solutions of aluminium sulphate and copper sulphate. In which test tube or test tubes will she observe colour change? On the basis of this experiment, state which one is the most reactive metal and why.
Ans:
Test tube A (Al + FeSO4): Colour change (Green to colourless).
Test tube B (Al + CuSO4): Colour change (Blue to colourless).
Test tube C (Fe + Al2(SO4)3): No change.
Test tube D (Fe + CuSO4): Colour change (Blue to light green).
Most reactive: Aluminium. It displaces both Fe and Cu.
Test tube B (Al + CuSO4): Colour change (Blue to colourless).
Test tube C (Fe + Al2(SO4)3): No change.
Test tube D (Fe + CuSO4): Colour change (Blue to light green).
Most reactive: Aluminium. It displaces both Fe and Cu.
25. What is observed when a solution of sodium sulphate is added to a solution of barium chloride taken in a test tube? Write equation for the chemical reaction involved and name the type of reaction in this case.
Ans: A white precipitate of Barium Sulphate is formed.
Equation: Na2SO4 + BaCl2 → BaSO4(↓) + 2NaCl.
Type: Double Displacement Reaction.
Equation: Na2SO4 + BaCl2 → BaSO4(↓) + 2NaCl.
Type: Double Displacement Reaction.
26. The values of current (I) flowing through a given resistor of resistance (R), for the corresponding values of potential difference (V) across the resistor are as given below:
V (volts): 0.5, 1.0, 1.5, 2.0, 2.5, 3.0, 4.0, 5.0
I (amperes): 0.1, 0.2, 0.3, 0.4, 0.5, 0.6, 0.8, 1.0
Plot a graph between current (I) and potential difference (V) and determine the resistance (R) of the resistor.
V (volts): 0.5, 1.0, 1.5, 2.0, 2.5, 3.0, 4.0, 5.0
I (amperes): 0.1, 0.2, 0.3, 0.4, 0.5, 0.6, 0.8, 1.0
Plot a graph between current (I) and potential difference (V) and determine the resistance (R) of the resistor.
Ans: The graph of V vs I will be a straight line passing through the origin. Slope = ΔV/ΔI.
From data: R = V/I = 0.5/0.1 = 5 Ω. (Consistent across all points).
From data: R = V/I = 0.5/0.1 = 5 Ω. (Consistent across all points).
27. List the steps of preparation of temporary mount of a leaf peel to observe stomata.
Ans:
1. Remove a peel from the lower surface of a leaf.
2. Stain with safranin.
3. Place on a slide with a drop of glycerine.
4. Cover with a coverslip and observe under a microscope.
2. Stain with safranin.
3. Place on a slide with a drop of glycerine.
4. Cover with a coverslip and observe under a microscope.