QUARTERLY EXAMINATION- 2024
SCHOOL EDUCATION – VILLUPURAM DISTRICT
SCIENCE ANSWER KEY
Answer all the questions.
| Q.No | Answer |
|---|---|
| 1 | d) both a and c. |
| 2 | b) infinity |
| 3 | d) (a) or (b) |
| 4 | c) ohm |
| 5 | a. 6.023 x 10²³ |
| 6 | a) 17th |
| 7 | c. Water |
| 8 | c) conjoint |
| 9 | b) 33 segments |
| 10 | (a) medulla oblongata |
| 11 | a) Pancreas |
| 12 | c) Graffian follicle |
Answer any seven questions. (Q.no 22 is compulsory)
Inertia: The inherent property of a body to resist any change in its state of rest or the state of uniform motion, unless it is influenced upon by an external unbalanced force.
Type:
- a. Inertia of rest
- b. Inertia of motion
- c. Inertia of direction
Power of accommodation:
The ability of the eye lens to focus nearby as well as the distant objects is called power of accommodation of the eye.
The number of atoms present in the molecule is called its atomicity.
Correct statement: Solutions which contain two components are called binary solution.
Correct statement: Moseley's periodic table is based on atomic number.
Respiratory quotient is the ratio of volume of carbon dioxide liberated and the volume of oxygen consumed during respiration.
(or)
Respiratory quotient = Volume of CO₂ liberated / Volume of O₂ consumed
SA node is capable of initiating impulse which can stimulate the heart muscles to contract.
- a. Cyton
- b. Fore brain
- c. Hind brain
- d. Peripheral nervous system
- a. Exine
- b. Intine
- c. Generative cell
- d. Vegetative nucleus
During DNA replication, the short segments of DNA found in the lagging strand are called Okazaki fragments.
Sol: q = 12C, t = 5 s
I = q/t
I = 12/5
I = 2.4 A
Answer any seven questions. (Q.no 32 is compulsory)
Properties of light: (Any four points)
- Light is a form of energy.
- Light always travels along a straight line.
- Light does not need any medium for its propagation. It can even travel through vacuum.
- The speed of light in vacuum or air is, c = 3 × 10⁸ ms⁻¹.
- Since, light is in the form of waves, it is characterized by a wavelength (λ) and a frequency (ν), which are related by the following equation: c = ν λ (c - velocity of light).
- Different coloured light has different wavelength and frequency.
- Among the visible light, violet light has the lowest wavelength and red light has the highest wavelength.
- When light is incident on the interface between two media, it is partly reflected and partly refracted.
| Real gas | Ideal gas |
|---|---|
| Molecules or atoms of a gases interact with each other with a definite amount of intermolecular or inter atomic force of attraction | Atoms or molecules of a gas do not interact with each other |
| At very high temperature or low pressure there is no interatomic or intermolecular force of attraction | At very high temperature or low pressure the interatomic or intermolecular force of attraction is weak |
At a constant temperature, the steady current 'I' flowing through a conductor is directly proportional to the potential difference ‘V' between the two ends of the conductor.
- Aluminium
- Aluminium oxide
Solutions which are made of one solute and one solvent (two components) are called binary solutions.
Parasitic adaptation of leech: (Any four points)
- Blood is sucked by pharynx.
- Anterior and posterior ends of the body are provided with suckers by which the animal attaches itself to the body of the host.
- The three jaws inside the mouth, causes a painless Y-shaped wound in the skin of the host.
- The salivary glands produce hirudin which does not allow the blood to coagulate.
- Blood is stored in the crop.
Importance of transpiration: (Any four points)
- Creates transpirational pull for transport of water.
- Supplies water for photosynthesis.
- Transports minerals from soil to all parts of the plant.
- Cools the surface of the leaves by evaporation.
- Keeps the cells turgid; hence, maintains their shape.
- Application of gibberellins on plants stimulate extraordinary elongation of internode.
- Treatment of rosette plants with gibberellin induces sudden shoot elongation followed by flowering.
- Gibberellins promote the production of male flowers in monoecious plants.
- Gibberellins break dormancy of potato tubers.
- Gibberellins are efficient than auxins in inducing the formation of seedless fruit - Parthenocarpic fruits.
The hormones secreted by endocrine glands are called chemical messengers.
The fusion of sperm with the secondary nucleus to form the primary endosperm nucleus is called triple fusion.
Vas deferens, epididymis, seminal vesicle, prostate gland and penis.
Allosomes are chromosomes which are responsible for determining the sex of an individual.
i) If both A and R are true and R is correct explanation of A.
Because the ventricles have to pump out blood with force away from the heart.
CNS- Central Nervous System
= 2[H] + 1[O]
= 2[1] + 1[16]
= 2 + 16
= 18 gram
negative, positive
Answer all the questions.
- Propulsion of rockets is based on the law of conservation of linear momentum as well as Newton's III law of motion.
- When the rocket is fired, this fuel is burnt and a hot gas is ejected with a high speed from the nozzle of the rocket, producing a huge momentum.
- To balance this momentum, an equal and opposite reaction force is produced in the combustion chamber, which makes the rocket project forward.
- According to the conservation of linear momentum, when the mass of the rocket decreases with altitude, which results in the gradual increase in velocity of the rocket.
- At one stage, it reaches a velocity, which is sufficient to just escape from the gravitational pull of the Earth called escape velocity.
| Convex lens | Concave lens |
|---|---|
| Thicker at the middle, thinner at the edges | Thinner at the middle, thicker at the edges |
| Converges the light | Diverges the light |
When the temperature of a gas is kept constant, the volume of a fixed mass of gas is inversely proportional to its pressure.
When sunlight passes through the atmosphere, the blue colour (shorter wavelength) is scattered to a greater extent. This scattering causes the sky to appear in blue colour.
Current is defined as the rate of flow of charges in a conductor.
Light Emitting Diode
- An atom is no longer indivisible.
- Atoms of the same element may have different atomic mass.
- Atoms of different elements may have same atomic masses.
- Atoms of one element can be transmuted into atoms of other elements by artificial transmutation.
- Atoms may not always combine in a simple whole number ratio.
- Atom is the smallest particle that takes part in a chemical reaction.
- The mass of an atom can be converted into energy E = mc².
Dilute or concentrated nitric acid.
Reason: it renders aluminium passive due to the formation of an oxide film on its surface.
1. water 2. Moisture air
| Hygroscopic substances | Deliquescent substances |
|---|---|
| When exposed to the atmosphere they absorb moisture and do not dissolve | When exposed to the atmospheric air they absorb moisture and dissolve. |
| Do not change its physical state on exposure to air | Change its physical state on exposure to air |
| May be amorphous solids or liquids | They are crystalline solids |
Hygroscopic substances: Conc. Sulphuric acid, Silica Gel
Deliquescent substances: Copper sulphate penta hydrate, Calcium chloride, and Gypsum salt
Photosynthesis is a process by which autotrophic organisms like green plants, algae and chlorophyll containing bacteria utilize the energy from sunlight to synthesize their own food.
| Aerobic respiration | Anaerobic respiration |
|---|---|
| Take place with the help of oxygen | Takes place without oxygen. |
| Formation of carbon dioxide, water and energy. | Formation of ethanol |
In rabbit the teeth are of different types. Hence, the dentition is called heterodont.
Thyroid hormone
- Transport of respiratory gases (Oxygen and CO₂).
- Transport of digested food materials to the different body cells.
- Transport of hormones.
- Transport of nitrogenous excretory products like ammonia, urea and uric acid.
- It is involved in protection of the body and defense against diseases.
- It acts as buffer and also helps in regulation of pH and body temperature.
- It maintains proper water balance in the body.
cerebellum, pons and medulla oblongata.
Treatment of rosette plants with gibberellin induces sudden shoot elongation followed by flowering is called bolting.
May 28