10th Science Quarterly Exam 2024 - Solved Question Paper
PART A
Choose the best answer (12x1 = 12)
1. One kilogram force equals to
Answer: c) 98x10⁴ dyne
Explanation: 1 kgf = 9.8 N. 1 N = 10⁵ dyne. So, 1 kgf = 9.8 × 10⁵ dyne = 98 × 10⁴ dyne.
2. To project the rockets, which of the following principles is / are required?
Answer: d) both a and c
3. The eye defect presbyopia can be corrected by
Answer: d) Bifocal lenses
4. The value of universal gas constant
Answer: d) 8.31 J mol⁻¹k⁻¹
5. Which of the following is triatomic molecule?
Answer: c) carbon dioxide (CO₂)
6. The basis of modern periodic law is
Answer: a) Atomic number
7. Which of the following is the 'Universal Solvent'
Answer: c) water
8. A solution was prepared by dissolving 25g of sugar in 100 gram of water. The mass percentage of solute is
Answer: a) 20%
Explanation: Mass of solute = 25g. Mass of solvent = 100g. Mass of solution = 25 + 100 = 125g. Mass % = (Mass of solute / Mass of solution) × 100 = (25 / 125) × 100 = 20%.
9. Which is formed during anaerobic respiration
Answer: b) Ethyl Alcohol
10. Which of the following has "Incomplete four chambered heart"?
Answer: c) reptiles
11. Avena coleoptile test was conducted by
Answer: d) F.W.Went
12. The plant, which propagates with the help of its leaves is
Answer: d) Bryophyllum
PART B
Write answers for any seven of the followings (Question No 22 is compulsory) (7x2=14)
13. How does an astronaut float in a space shuttle?
An astronaut floats in a space shuttle because both the astronaut and the shuttle are in a constant state of freefall towards the Earth. Since they are falling together at the same rate, the astronaut appears to be weightless and floats relative to the shuttle.
14. State: Snell's Law?
Snell's Law states that the ratio of the sine of the angle of incidence (i) to the sine of the angle of refraction (r) is a constant, for the light of a given colour and for the given pair of media. This constant is known as the refractive index.
Mathematically, sin(i) / sin(r) = constant (µ).
15. What are the effects of (i) Temperature (ii) Pressure on the solubility of CO₂ in water?
(i) Temperature: The solubility of a gas like CO₂ in a liquid (water) decreases with an increase in temperature.
(ii) Pressure: The solubility of CO₂ in water increases with an increase in pressure (Henry's Law).
16. Fill in the blanks
a) The atomicity of phosphorous is ........
b) The Number of Neutrons present in ₂₀Ca⁴⁰ is .......
a) The atomicity of phosphorous is 4 (P₄).
b) The Number of Neutrons present in ₂₀Ca⁴⁰ is 20. (Neutrons = Mass Number - Atomic Number = 40 - 20 = 20).
17. Match the followings
| 1. Galvanisation | Silver tin amalgam |
| 2. Dental filling | Noble gas elements |
| 3. Group 18 elements | Heating in the absence of Air |
| 4. Calcination | Coating with Zn |
| 1. Galvanisation | Coating with Zn |
| 2. Dental filling | Silver tin amalgam |
| 3. Group 18 elements | Noble gas elements |
| 4. Calcination | Heating in the absence of Air |
18. Why should the light dependent reaction occur before the light independent reaction?
The light-dependent reaction must occur first because it captures light energy and converts it into chemical energy in the form of ATP and NADPH. These energy-rich molecules are essential to power the light-independent reaction (Calvin cycle), where CO₂ is fixed into sugar.
19. Write dental formula of Rabbit?
The dental formula of a rabbit is: I 2/1, C 0/0, P 3/2, M 3/3. Total = 28 teeth.
20. Who discovered Rh factor? Why do it so call?
The Rh factor was discovered by Karl Landsteiner and Alexander Wiener in 1940. It is called 'Rh factor' because it was first discovered in the blood of the Rhesus monkey.
21. Draw the structure of NEURON label the following parts a) Dendrites b) Axon c) Myelin Sheath d) Nodes of Ranvier
(Drawing is not possible in text, but the parts are described below)
- a) Dendrites: Short, branched extensions that receive nerve impulses from other neurons.
- b) Axon: A long, slender projection that conducts electrical impulses away from the neuron's cell body.
- c) Myelin Sheath: An insulating layer that forms around the axon, allowing electrical impulses to transmit quickly.
- d) Nodes of Ranvier: Gaps in the myelin sheath between adjacent Schwann cells, which facilitate the rapid conduction of nerve impulses.
22. If the earth shrinks to 50% of its real radius, its mass remaining the same, what will be the weight of a body on the earth?
Let initial radius be R and mass be M. The acceleration due to gravity g = GM/R². The weight of a body W = mg = m(GM/R²).
New radius R' = R/2.
New gravity g' = GM/(R')² = GM/(R/2)² = GM/(R²/4) = 4(GM/R²) = 4g.
New weight W' = mg' = m(4g) = 4(mg) = 4W.
The weight of the body will become four times its original weight.
PART C
Write answers for any seven of the followings (Question 32 is compulsory) (7x4=28)
23. a) State Joules Law of heating b) Calculate the current and the resistance of a 100 W, 200v electric bulb in a electric circuit?
a) Joule's Law of Heating: It states that the heat (H) produced in a conductor is directly proportional to: (i) the square of the current (I²) flowing through it, (ii) the resistance (R) of the conductor, and (iii) the time (t) for which the current flows. Mathematically, H = I²RT.
b) Calculation:
Given: Power (P) = 100 W, Voltage (V) = 200 V.
Current (I): P = VI ⇒ I = P/V = 100W / 200V = 0.5 A.
Resistance (R): V = IR ⇒ R = V/I = 200V / 0.5A = 400 Ω.
32. a) 1.5g of solute is dissolved in 15g of water to form a saturated solution at 298k. Find out the solubility of the solute at the temperature? b) A is metal. It belongs to the Boron family in the modern periodic table. It is one of the best reducing agent so, it reduces the iron oxide in to iron. Metal A is used in the manufacture of cooking vessel. Identify 'A'. Write the chemical equation for reducing character.
a) Solubility Calculation:
Solubility = (Mass of solute / Mass of solvent) × 100
Given: Mass of solute = 1.5 g, Mass of solvent (water) = 15 g.
Solubility = (1.5 / 15) × 100 = 0.1 × 100 = 10 g.
(This means 10g of solute can be dissolved in 100g of solvent at 298K).
b) Identification and Equation:
The metal in the Boron family (Group 13) used for cooking vessels is Aluminium (Al).
It acts as a strong reducing agent in the thermite reaction.
Chemical Equation: 2Al + Fe₂O₃ → Al₂O₃ + 2Fe + Heat
PART D
Write Answers for the followings (3x7=21)
33. a) List any three properties of light? b) Differentiate the eye defects Myopia Vs Hypermetropia (two points only) c) Power of a lens is-4D calculate its focal length.
(or)
a) What is meant by electric current? b) Which Instrument is used to measure the electric current? c) How should it be connected in a circuit? d) Define: Calorie
Answer for the first choice:
a) Three properties of light:
1. Light travels in a straight line (Rectilinear propagation).
2. Light can be reflected (bounces off surfaces).
3. Light can be refracted (bends when passing from one medium to another).
b) Myopia vs Hypermetropia:
| Myopia (Nearsightedness) | Hypermetropia (Farsightedness) |
| The image is formed in front of the retina. | The image is formed behind the retina. |
| It is corrected using a concave lens. | It is corrected using a convex lens. |
c) Calculation:
Power (P) = -4D.
Focal length (f) = 1/P = 1 / (-4) = -0.25 m.
In centimeters, f = -0.25 × 100 = -25 cm.
34. a) Derive the relationship between relative molecular mass and vapour density b) Calculate the number of water molecules present in one drop of water which weighs 0.18g
(or)
a) Along with cryolite and alumina another substance is added to the electrolyte mixture, name the substance and give one reason for the addition? b) Differentiate: Hygroscopic substances, deliquescence substances
Answer for the first choice:
a) Relationship between Relative Molecular Mass and Vapour Density:
Vapour Density (V.D.) is the ratio of the mass of a certain volume of a gas or vapour to the mass of the same volume of hydrogen at the same temperature and pressure.
V.D. = (Mass of a given volume of gas) / (Mass of the same volume of H₂)
By Avogadro's law, volume is proportional to the number of molecules. So,
V.D. = (Mass of 'n' molecules of gas) / (Mass of 'n' molecules of H₂)
V.D. = (Mass of 1 molecule of gas) / (Mass of 1 molecule of H₂)
V.D. = (Molecular mass of gas) / (Molecular mass of H₂)
Since molecular mass of H₂ is 2,
V.D. = Molecular mass / 2
Therefore, Relative Molecular Mass = 2 × Vapour Density.
b) Calculation of water molecules:
Given mass of water = 0.18 g.
Molar mass of water (H₂O) = (2×1) + 16 = 18 g/mol.
Number of moles = Given mass / Molar mass = 0.18 g / 18 g/mol = 0.01 moles.
Number of molecules = Number of moles × Avogadro's number (Nₐ)
Number of molecules = 0.01 × 6.022 × 10²³ = 6.022 × 10²¹ molecules.
35. a) How is the structure of DNA organised? b) What is the Biological significance of DNA
(or)
a) Enumerate 3 functions of Blood? b) Explain any 2 parasitic adaptations of leeches? c) Draw and label the structure of oxysomes?
Answer for the 'or' choice:
a) Three functions of Blood:
1. Transport: It transports oxygen from the lungs to tissues, carbon dioxide from tissues to lungs, nutrients from the digestive system to cells, and hormones from glands to target organs.
2. Protection: White blood cells (leukocytes) defend the body against infections and diseases. Platelets help in blood clotting to prevent excessive blood loss.
3. Regulation: It helps regulate body temperature, pH balance, and water content of cells.
b) Two parasitic adaptations of leeches:
1. Suckers: Leeches have an anterior and posterior sucker for firm attachment to the host's body.
2. Secretion of Hirudin: Their saliva contains an anticoagulant called hirudin, which prevents the host's blood from clotting, ensuring a continuous supply of blood.
c) Structure of Oxysomes:
(Drawing is not possible in text, but the structure is described below)
Oxysomes, also known as F₀-F₁ particles, are found on the inner mitochondrial membrane. They are responsible for ATP synthesis. The structure consists of three parts:
- The Head (F₁ particle): A spherical part that projects into the mitochondrial matrix. It contains the ATP synthase enzyme site.
- The Stalk: Connects the head piece to the base.
- The Base (F₀ particle): Embedded in the inner mitochondrial membrane and acts as a proton channel.