p Pb (NO₃)₂(s) ---- > q PbO(s) + r NO₂(g) + O₂(g)

1. 2,2,4
2. 2,4,2
3. 2,4,4
4. 4,2,2

1. a – (ii), b – (i), c – (iii), d – (iv)
2. a – (iii), b – (i), c – (iv), d – (ii)
3. a – (iv), b – (ii), c – (iii), d – (i)
4. a – (iii), b – (ii), c – (i), d – (iv)

1. HNO₃
2. C₂H₅OH
3. H₂SO₄
4. CO₂ in water

1. A is strongly basic and B is a weak base.
2. A is strongly acidic and B is a weak acid.
3. A has a pH greater than 7 and B has a pH less than 7.
4. A has a pH less than 7 and B has a pH greater than 7.

1. Combination reaction
2. Decomposition reaction
3. Displacement reaction
4. Double displacement reaction

1. Y and Z are metals
2. Y and X are non-metals
3. X is a non-metal and Y is a metal
4. Y is a non-metal and Z is a metal

1. Burning of candle
2. Cooking of food
3. Decomposition of vegetable matter
4. Reaction of sodium with air

1. ethanol in yeast
2. Lactic acid in muscle cells
3. Carbon dioxide in yeast cells
4. Carbon dioxide in human cells

1. Contraction of the left atrium
2. Contraction of the left ventricle
3. Relaxation of the right atrium
4. Relaxation of the right ventricle

1. Longer large intestine
2. Smaller large intestine
3. Smaller small intestine
4. Longer small intestine

1. Salivation
2. Hunger control
3. Posture and balance
4. Regulation of blood pressure

1. Male snails have dominant genetic makeup.
2. Female snails have dominant genetic makeup.
3. Expression of sex chromosomes can change in a snail’s lifetime.
4. Sex is not genetically determined in snails.

1. A ray parallel to principal axis
2. A ray passing through the centre of curvature and incident obliquely
3. A ray passing through the principal focus and incident obliquely
4. A ray incident obliquely to the principal axis, at the pole of the mirror

1. It is the first trophic level which absorbs 1% of light energy directly from the source.
2. It utilizes the most of the chemical energy for its own respiration, growth, reproduction, movement etc.
3. It utilizes 10% of light energy and transfers the rest to the next trophic level.
4. It transfers only 10% of light energy to the next trophic level.

1. Natural replenishment of soil.
2. Enrichment of oxygen in atmosphere.
3. Waste decomposition.
4. Break-down of dead remains.

1. Both A and R are true, and R is the correct explanation of A.
2. Both A and R are true, but R is not the correct explanation of A.
3. A is true, but R is false.
4. A is false, but R is true.

1. Both A and R are true, and R is the correct explanation of A.
2. Both A and R are true, but R is not the correct explanation of A.
3. A is true, but R is false.
4. A is false, but R is true.

1. Both A and R are true, and R is the correct explanation of A.
2. Both A and R are true, and R is not the correct explanation of A.
3. A is true but R is false.
4. A is false but R is true

1. Both A and R are true, and R is the correct explanation of A.
2. Both A and R are true, but R is not the correct explanation of A.
3. A is true, but R is false.
4. A is false, but R is true.

1. Fe₂O₃ + 2Al → Al₂O₃ + 2Fe + heat
2. Pb(NO₃)₂ + 2KI → PbI₂( ↓) + 2KNO₃

A. List the steps for the synthesis of glucose by the plants. What special feature is found in desert plants related to this process?

B. Explain the role of the following enzymes in the process of digestion of food in humans:

• Salivary amylase
• Pepsin
• Trypsin
• Lipase

1. What is the type of lens used?
2. What is the nature of the image?
3. If the image formed is at a distance of 30 cm of the lens and the image is twice the size of the object, then where is the object placed?

View Answer

1. Convex lens because When we place any object between the optic center and principal focal length the image is formed on the same side of the object and is virtual, erect and enlarged.
2. Virtual, erect and enlarged
3. 𝑣= −30 𝑐𝑚 (object distance is negative according to the sign convention) 𝑚=2 (given)

1. The electric circuit in a clothes dryer contains two heaters X and Y in parallel. The above figure shows a circuit connected to 230 V power supply. When both switches are closed, the current in X is 3.5 A.
   1. Calculate the power developed in heater X.
   2. If the resistance of X is double and that of Y, calculate the current in heater Y.
2. The given figure shows two resistors X and Y connected in series to a battery. The power dissipated for this combination is 𝑷₁. When these resistors are connected in parallel to the same battery then the power dissipated is given by 𝑷₂ . Find out the ratio of 𝑷₁ / 𝑷₂

View Answer

1. ∵ X and Y are connected in parallel
   ⟹ Voltage remains same
   ∵ P= VI
   =230 x 3.5=805 W
   ∴ Power developed in heater X is 805 W
   
2. 
   

Ans:When the resistances are connected in series: 𝑅_𝑒𝑞 = 𝑅+2𝑅

When the resistances are connected in Parallel:

What impact will the process shown in the image have on Humans if they occupy the last trophic level? Explain.

Give reasons for the following:
(i) Certain metals are used for making cooking utensils.
(ii) Hydrogen gas does not evolve when certain metals except Mg & Mn react with nitric acid.

(i) In the given series of reactions, name the compounds X and Z.
(ii) Which type of reaction is X to Z?
(iii) You are given 3 unknown solutions A, B, and C with pH values of 6, 8, and 9.5 respectively. In which solution will the maximum number of hydronium ions be present? Arrange the given samples in the increasing order of H⁺ ion concentration.

Comment on the following statements:
(i) Bee sting is treated with baking soda paste, whereas wasp sting is treated with dilute vinegar.
(ii) Farmers treat soil with quicklime when tilling.
(iii) Ancient sculptures and marble structures are conserved by treating them with certain chemicals.

Water is used by the leaves of the plants for photosynthesis but rather than watering the leaves, we water the plant through the soil. How does this water reach the leaves of the plant?

In a family of four individuals, the father possessed long ears and the mother possessed short ears. If the parents had pure dominant and recessive traits respectively, then calculate the ratio of genetic makeup of F2 generation. Show a suitable cross.

1. What is the fundamental difference between hypermetropia and myopia in terms of the optical experience of the person ?
2. The diagram below shows a special case of an eye defect.

1. What is the defect that is shown in the figure?
2. State one cause for such a defect.
3. Explain with reason if a concave lens is used to correct the defect.

Resistance is a property of a conductor that depends on its length and cross-sectional area. Explain the relationship between resistance, length, and cross-sectional area. Also, define resistivity and its unit.

Mona was doing an experiment with a magnetic compass and a straight current-carrying wire. She observed that as she moved the compass away from the current-carrying wire, the deflection of the compass needle reduced. Explain why the deflection of the compass needle reduced as Mona moved the compass away from the current-carrying wire.

1. Explain why the deflection of the compass needle reduced as Mona moved away the compass needle from the current carrying wire.
2. Mention one thing that could have changed in the circuit of the wire that could increase the deflection of the needle.
3. Explain with reason what will be the direction of the magnetic field associated with the wire for the case described by the above figure.

A.

1. “Keerthi thinks that Substitution reaction occurs in saturated Hydrocarbons, on the contrary Krishi thinks, it occurs in unsaturated Hydrocarbons.” Justify with valid reasoning whose thinking is correct.
2. “Methane and Propane and their Isomers are used as fuels” Comment. Draw the electron dot structure of the immediate lower homologue of Propane. Give any two characteristics of homologues of a given homologous series.
3. A mixture of oxygen and ethyne is burnt for welding. Can you predict why a mixture of ethyne and air is not used?

B.

1. ‘A’ & ‘B’ are sodium salts of long-chain carboxylic acid and long-chain Sulphonic acid respectively. Which one of A or B will you prefer as a cleansing agent while using underground water (hand pump water)? Give the reason for your answer.
2. Elaborate on the process of cleansing action. Illustrate micelle with the help of a labelled diagram.
3. Write the chemical equation of the preparation of soap from an ester CH3COOCH3. What is the name of this process?

1. The image below shows a banana plant that is growing with the help of suckers. These suckers are small plant stem outgrowths that can be separated from the main plant, planted separately, and grow into a new plant subsequently.

1. Give the name and type of reproduction shown in the image above.
2. List two advantages a farmer has in using the type of reproduction mentioned above.
3. Explain how this plant will be involved in the process of pollination.
4. Why is the offspring of this banana plant not absolutely identical to its parent plant?
OR
2. The image below shows a developing fetus in the mother's womb. The fetus is connected to the placenta via the umbilical cord, which contains the umbilical vein and artery.

1. Name two substances that move through the blood vessels.
2. If the placenta has fewer villi, how will it affect the baby's growth?
3. Name the region where the embryo develops inside the female body. Explain how this region is adapted for nourishing the baby.
4. Some fetal cells fall into the amniotic fluid and can be collected through careful procedures. If these cells contain the XY chromosome:
   1. What is the sex of the fetus?
   2. How is prenatal sex determination misused?

1. .The above circuit is a part of an electrical device. Use the information given in the question to calculate the following:
   1. Potential Difference across R₂.
   2. Value of the resistance R₂.
   3. Value of resistance R₁.
OR
2. 
   As shown in the figure above, A and B are two lamps. Lamp A is rated at 12 V, 24W. Lamp B is rated at 6.0 V. When lamp B operates at its rated voltage, the current in it is 3.0 A. The values of R₁ and R₂ are chosen so that both lamps operate at their rated voltages. Based on the information given, answer the following:
   1. Calculate the current in Lamp A.
   2. State and give reason for the reading of the Voltmeter.
   3. Calculate the resistance of R₂.
   4. Find the value of the resistance R₁.

1. Derive the names of A, Y, Z, M, P & R
Attempt either subpart B or C.
2. Improvise an activity to test Z
OR
3. Name the process in which compounds X, Y & Z are formed from A. Justify your response.

The above image is that of a reflecting telescope. Reflecting telescopes revolutionised our ways of looking into the sky. They employ mirrors to gather and focus light, rather than relying solely on lenses as in their refracting counterparts. These telescopes utilise precisely shaped and polished mirrors to capture incoming light and reflect it to a focal point, where it forms an image for observation.

(i) What kind of image of a star is seen by the observer at the eyepiece?

(ii) What kind of mirror is used in this reflecting telescope?

(iii) Explain with reason what kind of optical device (type of lens or mirror) that is used at the eyepiece.

(iv) What is the role of the plane mirror in the telescope?