Date: 31-07-2024
Time: 1.30 Hrs.
Tenkasi District
Common First Mid Term Test - 2024
Standard 10 SCIENCE
Part - I
10 × 1 = 10Answer all the questions.
-
Choose the best option:
- The inertia of a body depends on __________.
- Magnification of a convex lens is __________.
- Mass of 1 mole of nitrogen atom is __________.
- __________ is a relative periodic property.
- Casparian strips are present in the __________ of the root.
- Mammals are __________ animals.
- During transpiration, there is a loss of __________.
- 'Heart of heart' is called __________.
- Which substance gives red colour to blood?
- Bipolar neurons are found in the __________.
Part - II
5 × 2 = 10Answer ANY 5 questions. Question No. 19 is compulsory.
- State Newton's laws of motion.
- Why does the sky appear blue in colour?
- State two conditions necessary for the rusting of iron.
- State Avogadro's law.
- Name the acid that renders aluminium passive.
- What is the function of a chloroplast?
- Why is the colour of blood red?
- Name the parts of the hindbrain.
- Calculate the gram molar mass of the following.
Part - III
4 × 4 = 16Answer any 4 questions. Question No. 25 is compulsory.
- Differentiate between mass and weight.
- a) State Snell's law.
b) State Rayleigh's law of scattering. - a) Define Atomicity.
b) Give any two examples of heteroatomic molecules. - a) What is respiratory quotient?
b) Write the reaction for photosynthesis. - Enumerate the functions of blood.
- A is a silvery-white metal. 'A' combines with O2 to form 'B' at 800°C. An alloy of 'A' is used in making aircraft. Find A and B.
Part - IV
2 × 7 = 14Answer all the questions.
-
a) Differentiate the eye defects Myopia and Hypermetropia.
b) Define dispersion of light.
(OR)
a) Give the salient features of 'Modern atomic theory'.
b) Define Relative atomic mass. -
a) Differentiate between Monocot and Dicot root.
b) Draw and label the structure of oxysomes.
(OR)
a) Explain the male reproductive system of a rabbit with a labelled diagram.
Complete Solutions
Part - I: Answers
- c) mass of the object - Inertia is the natural tendency of an object to resist a change in its state of rest or uniform motion, and it is directly proportional to the object's mass.
- b) either positive or negative - A convex lens produces a real, inverted image (negative magnification) or a virtual, erect image (positive magnification) depending on the object's position.
- d) 14g - One mole of any atom has a mass in grams equal to its atomic mass number. The atomic mass of a nitrogen atom (N) is 14 amu. Therefore, one mole of nitrogen atoms weighs 14g. (Note: one mole of nitrogen molecules, N2, would be 28g).
- d) Electronegativity - Electronegativity measures an atom's ability to attract shared electrons in a chemical bond. It is a relative value, unlike atomic/ionic radii and electron affinity which are properties of isolated atoms.
- d) Endodermis - Casparian strips are waterproof bands of suberin found in the cell walls of the endodermis in plant roots, regulating water and mineral uptake.
- b) Warm blooded - Mammals are endothermic, meaning they maintain a constant internal body temperature regardless of the external environment.
- c) Water - Transpiration is the biological process of water vapor loss from the surfaces of plants, primarily through stomata in the leaves.
- a) SA node - The Sinoatrial (SA) node is the natural pacemaker of the heart, initiating the electrical impulses that cause the heart to contract.
- a) Haemoglobin - Haemoglobin is the iron-containing protein in red blood cells that binds to oxygen and gives blood its characteristic red colour.
- a) retina of eye - Bipolar neurons are specialized nerve cells with two extensions (an axon and a dendrite) and are a key component of the neural pathways for senses like sight (retina).
Part - II: Answers
11. State Newton's laws of motion.
- Newton's First Law (Law of Inertia): Every body continues to be in its state of rest or the state of uniform motion along a straight line unless it is acted upon by an external force.
- Newton's Second Law (Law of Force): The force acting on a body is directly proportional to the rate of change of its linear momentum and the change in momentum takes place in the direction of the force. ($F = ma$)
- Newton's Third Law (Law of Action and Reaction): For every action, there is an equal and opposite reaction.
12. Why does the sky appear blue in colour?
The sky appears blue due to a phenomenon called Rayleigh scattering. When sunlight enters the Earth's atmosphere, it is scattered in all directions by the gas molecules and other tiny particles. According to Rayleigh's scattering law, the amount of scattering is inversely proportional to the fourth power of the wavelength of light. Since blue light has a shorter wavelength than red light, it is scattered much more effectively. This scattered blue light reaches our eyes from all directions, making the sky appear blue.
13. State two conditions necessary for the rusting of iron.
The two essential conditions for the rusting of iron are:
- Presence of Oxygen (from the air).
- Presence of Water or moisture (humidity).
14. State Avogadro's law.
Avogadro's law states that "equal volumes of all gases under the same conditions of temperature and pressure contain the equal number of molecules." Mathematically, it can be expressed as $V \propto n$, where V is the volume of the gas and n is the number of moles.
15. Name the acid that renders aluminium passive.
Concentrated nitric acid (HNO3) renders aluminium passive. It does this by forming a thin, non-porous, and non-reactive protective layer of aluminium oxide (Al2O3) on the surface of the metal, which prevents further reaction.
16. What is the function of a chloroplast?
The primary function of a chloroplast is to conduct photosynthesis. It contains the green pigment chlorophyll, which captures light energy from the sun and converts it into chemical energy in the form of glucose (food for the plant). This process also releases oxygen as a byproduct.
17. Why is the colour of blood red?
Blood is red due to the presence of a protein called haemoglobin within the red blood cells. Haemoglobin contains iron atoms, which bind with oxygen. When oxygen is bound to haemoglobin, it forms oxyhaemoglobin, which has a bright red colour, giving arterial blood its characteristic shade.
18. Name the parts of the hindbrain.
The hindbrain is composed of three main parts:
- Pons
- Medulla Oblongata
- Cerebellum
19. Calculate the gram molar mass of the following.
i) Water (H2O)
- Atomic mass of Hydrogen (H) = 1 g/mol
- Atomic mass of Oxygen (O) = 16 g/mol
- Gram molar mass of H2O = (2 × Atomic mass of H) + (1 × Atomic mass of O)
- = (2 × 1) + (1 × 16) = 2 + 16 = 18 g/mol
- Gram molar mass of Water is 18 g/mol.
ii) Carbon Dioxide (CO2)
- Atomic mass of Carbon (C) = 12 g/mol
- Atomic mass of Oxygen (O) = 16 g/mol
- Gram molar mass of CO2 = (1 × Atomic mass of C) + (2 × Atomic mass of O)
- = (1 × 12) + (2 × 16) = 12 + 32 = 44 g/mol
- Gram molar mass of Carbon Dioxide is 44 g/mol.
Part - III: Answers
20. Differentiate between mass and weight.
| Feature | Mass | Weight |
|---|---|---|
| Definition | It is the quantity of matter contained in a body. | It is the gravitational force exerted on a body due to Earth's gravity. |
| Nature | It is a scalar quantity (has only magnitude). | It is a vector quantity (has magnitude and direction). |
| SI Unit | kilogram (kg) | newton (N) |
| Constancy | It is constant everywhere. | It varies from place to place depending on the acceleration due to gravity (g). |
| Measurement | Measured using a physical balance. | Measured using a spring balance. |
21. a) State Snell's law.
b) State Rayleigh's law of scattering.
a) Snell's Law:
Snell's law of refraction 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, which is equal to the ratio of the refractive indices of the two media.
Mathematically: $ \frac{\sin i}{\sin r} = \frac{n_2}{n_1} = constant $
Where $n_1$ is the refractive index of the first medium and $n_2$ is the refractive index of the second medium.
b) Rayleigh's Law of Scattering:
Rayleigh's law of scattering states that the amount of scattering of light is inversely proportional to the fourth power of its wavelength ($\lambda$).
Mathematically: $ \text{Amount of Scattering} \propto \frac{1}{\lambda^4} $
This means shorter wavelengths (like blue and violet) are scattered much more strongly than longer wavelengths (like red and orange).
22. a) Define Atomicity.
b) Give any two examples of heteroatomic molecules.
a) Define Atomicity:
Atomicity is defined as the total number of atoms present in one molecule of an element, compound, or substance. For example, the atomicity of an oxygen molecule (O2) is 2, and the atomicity of an ozone molecule (O3) is 3.
b) Give any two examples of heteroatomic molecules:
Heteroatomic molecules are molecules composed of atoms of two or more different elements. Two examples are:
- Water (H2O): Composed of Hydrogen and Oxygen atoms.
- Ammonia (NH3): Composed of Nitrogen and Hydrogen atoms.
23. a) What is respiratory quotient?
b) Write the reaction for photosynthesis.
a) What is respiratory quotient?
The Respiratory Quotient (RQ) is the ratio of the volume of carbon dioxide ($CO_2$) evolved to the volume of oxygen ($O_2$) consumed during respiration over a period of time.
Formula: $ RQ = \frac{\text{Volume of } CO_2 \text{ evolved}}{\text{Volume of } O_2 \text{ consumed}} $
b) Write the reaction for photosynthesis.
The balanced chemical equation for photosynthesis is:
$ 6CO_2 + 6H_2O \xrightarrow{\text{Sunlight, Chlorophyll}} C_6H_{12}O_6 + 6O_2 $
Where: Carbon Dioxide + Water yields Glucose (food) + Oxygen.
24. Enumerate the functions of blood.
The main functions of blood are:
- Transport: Carries oxygen from the lungs to tissues, and carbon dioxide from tissues to the lungs. It also transports nutrients (like glucose), hormones, enzymes, and waste products (like urea).
- Regulation: Helps maintain body temperature (thermoregulation), pH balance, and water balance within the body.
- Protection: Plays a crucial role in the immune system through white blood cells that fight infection. Platelets and clotting factors in blood prevent excessive blood loss by forming clots at injury sites.
25. A is a silvery-white metal. 'A' combines with O2 to form 'B' at 800°C. An alloy of 'A' is used in making aircraft. Find A and B.
Let's deduce the identity of A and B step-by-step:
- Clue 1: "An alloy of 'A' is used in making aircraft." This strongly suggests that metal 'A' is Aluminium (Al), as its alloys (like Duralumin) are widely used in the aerospace industry due to their low density and high strength.
- Clue 2: "'A' is a silvery-white metal." Aluminium is indeed a silvery-white metal. This fits the description.
- Clue 3: "'A' combines with O2 to form 'B' at 800°C." Aluminium (A) reacts with Oxygen (O2) to form Aluminium Oxide (B). The reaction is:
$ 4Al + 3O_2 \rightarrow 2Al_2O_3 $
Therefore:
- A is Aluminium (Al)
- B is Aluminium Oxide (Al2O3)
Part - IV: Answers
26. (First Choice)
a) Differentiate the eye defects Myopia and Hypermetropia.
| Feature | Myopia (Near-sightedness) | Hypermetropia (Far-sightedness) |
|---|---|---|
| Vision Problem | Can see nearby objects clearly, but distant objects appear blurry. | Can see distant objects clearly, but nearby objects appear blurry. |
| Cause | Eyeball is too long, or the focal length of the eye lens is too short. | Eyeball is too short, or the focal length of the eye lens is too long. |
| Image Formation | The image of a distant object is formed in front of the retina. | The image of a nearby object is formed behind the retina. |
| Correction | Corrected using a concave lens of appropriate power. | Corrected using a convex lens of appropriate power. |
b) Define dispersion of light.
Dispersion of light is the phenomenon of splitting a beam of white light into its seven constituent colours (VIBGYOR - Violet, Indigo, Blue, Green, Yellow, Orange, Red) when it passes through a transparent medium like a glass prism. This happens because the refractive index of the medium is different for different colours (wavelengths) of light. Violet light, having the shortest wavelength, bends the most, while red light, with the longest wavelength, bends the least.
26. (OR - Second Choice)
a) Give the salient features of 'Modern atomic theory'.
The salient features of Modern Atomic Theory are:
- Atom is no longer indivisible: An atom is composed of subatomic particles: protons, neutrons, and electrons.
- Atoms of the same element may not be identical: The existence of isotopes (atoms of the same element with different mass numbers, e.g., 12C and 14C) proves this.
- Atoms of different elements may have the same mass number: This is seen in isobars (atoms of different elements with the same mass number, e.g., 40Ar and 40Ca).
- Atom is the smallest particle that takes part in a chemical reaction: While it can be broken down, it remains the fundamental unit in chemical reactions.
- Mass of an atom can be converted into energy: This is described by Einstein's equation, E=mc2. This principle is fundamental to nuclear reactions.
- Atoms may not always combine in simple whole-number ratios: In some non-stoichiometric compounds, the ratio of atoms is not simple (e.g., in certain metal oxides).
b) Define Relative atomic mass.
Relative Atomic Mass (RAM) of an element is defined as the ratio of the average mass of one atom of the element to 1/12th of the mass of one atom of the Carbon-12 isotope.
It is a dimensionless quantity and is essentially a comparison of an atom's mass to a standard (the Carbon-12 atom). For example, the RAM of oxygen is approximately 16, meaning an average oxygen atom is about 16 times heavier than 1/12th of a Carbon-12 atom.
Part - IV: Answers
27. (First Choice)
a) Differentiate between Monocot and Dicot root.
| Feature | Monocot Root | Dicot Root |
|---|---|---|
| Xylem & Phloem | Polyarch condition (many xylem and phloem bundles, usually more than six). | Tetrarch condition (four xylem and phloem bundles). |
| Pith | Large and well-developed pith at the center. | Small or absent pith. |
| Cambium | Absent. Therefore, no secondary growth. | Present between xylem and phloem. Allows for secondary growth. |
| Cortex | Wide cortex. | Narrow cortex. |
| Example | Maize, Grass | Bean, Sunflower |
b) Draw and label the structure of oxysomes.
Description of Oxysome (F1 particle) Structure:
Oxysomes, also known as F0-F1 particles or elementary particles, are found on the inner mitochondrial membrane and are responsible for ATP synthesis. A diagram would show:
- The Inner Mitochondrial Membrane: A lipid bilayer shown as the base.
- F0 Particle (Base): This part is embedded within the inner membrane. It acts as a proton channel, allowing protons (H+) to flow through.
- Stalk: A short, rod-like structure connecting the base (F0) to the head (F1).
- F1 Particle (Head): A spherical or knob-like structure that protrudes into the mitochondrial matrix. This is the catalytic site where ADP and inorganic phosphate (Pi) are combined to synthesize ATP.
Function: As protons flow through the F0 channel from the intermembrane space to the matrix, they cause the F1 particle to rotate, which drives the synthesis of ATP. This process is called chemiosmosis.
27. (OR - Second Choice)
a) Explain the male reproductive system of a rabbit with a labelled diagram.
Description of the Male Reproductive System of a Rabbit:
The male reproductive system of a rabbit consists of the primary sex organs (testes) and accessory glands and ducts that produce and transport sperm.
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Testes:
- These are the primary reproductive organs that produce sperm and male sex hormones (testosterone).
- In rabbits, the testes are located outside the abdominal cavity within a sac-like structure called the scrotal sac. This keeps the testes at a slightly lower temperature than the body, which is essential for sperm production.
-
Epididymis:
- A long, coiled tube located on the surface of each testis.
- Sperm produced in the testes mature and are stored here.
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Vas Deferens (Sperm Duct):
- A tube that carries sperm from the epididymis up into the abdominal cavity.
- It joins with the duct from the seminal vesicle to form the ejaculatory duct.
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Urethra:
- A tube that extends from the urinary bladder through the penis to the outside.
- In males, it serves as a common passage for both urine and semen (the fluid containing sperm).
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Accessory Glands: These glands produce seminal fluid, which mixes with sperm to form semen. The fluid provides nourishment and motility to the sperm.
- Seminal Vesicles: Secrete an alkaline fluid rich in fructose, which provides energy for the sperm.
- Prostate Gland: Secretes a milky, slightly acidic fluid that contributes to sperm motility and viability.
- Cowper's Gland (Bulbourethral Gland): Secretes a clear, mucus-like fluid that lubricates the urethra and neutralizes any residual acidity from urine.
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Penis:
- The external copulatory organ used to transfer semen into the female's reproductive tract during mating.