Test 2 – June Batch

In respect of a jet engine and a rocket, both the given statements are correct.

Wavelength is the distance between two consecutive crests or troughs and 1 angstrom = 10–10m, joule is the unit of energy. Intensity of sound is measured in decibel. Frequency is measured in hertz (Hz).

The unit of temperature is kelvin, power is measured in watt, pressure in pascal and force in newton.

A piece of ice added to the drink cool it because ice takes latent heat from the drink for melting resulting in the cooling of the drink.

If ice collects on the freezer, the cooling in the refrigerator is affected adversely because ice is a poor conductor of heat.

Cold-blooded animals require much less energy to survive than warm-blooded animals.

Humans are diploid organisms by having two members or homologous chromosomes in a pair.
Total 23 pairs of chromosomes exist in each somatic cell of the body. Total 46 chromosomes occur. One particular pair individually in male and female determines their respective sex. This one pair is XX in females and XY in males. All the 46 chromosomes in pairs can be seen under microscope at metaphase stage in the cells which are undergoing mitosis.

The valves prevent the backward flow of blood. Valves are actually flaps (leaflets) that act as one-way inlets for blood coming into a ventricle and one-way outlets for blood leaving a ventricle.
A septum is a diving wall which is present between the the left side and the right side of the heart, which does not allow mixing of blood when oxygen-rich and carbon dioxide- rich blood reach the heart.
Our heart chambers are four hollow spaces within your heart. There are two atria (upper chambers) called your right atrium and left atrium. In addition, there are two ventricles (lower chambers) called right ventricle and left ventricle.

The surface from where the gaseous exchange (oxygen and carbon dioxide) takes place with the surrounding is called respiratory surface. The features of respiratory surface are:
▪️ It is extremely thin and moist
▪️ It has a large surface area
▪️ It is richly supplied with blood capillaries.
▪️ It is permeable to gases.

Applications of Ultrasonic Waves are: sending signals, for measuring the depth of sea, for cleaning cloths, aeroplanes, machinery parts of clocks, for removing lamp-shoot from the chimney of factories, in sterilizing of liquid and in Ultrasonography.

During respiration exchange of gases take place in the alveoli of the lungs.

Fishes have only two chambered heart and the blood is pumped to the gills, is oxygenated there, and passes directly to rest of the body. Thus, blood goes only once through the heart in the fish during one cycle of passage through the body. Fishes take in water through their mouths and force it past the gills where the dissolved oxygen is taken up by blood.

The opening and closing of the stomatal pores are a function of the guard cells. The stomatal pore opens when the guard cells swell when water flows into them and closes if the guard cells shrink when water flows out of them.

Deer is a herbivorous animal and eats grass which contains cellulose. It needs a longer small intestine to allow the cellulose present in the grass to be digested completely. On the other hand, tiger is carnivore and eats meat. It is easier to digest meat. So, the tiger which eat meat has a shorter 'small intestine.

Meningococcal meningitis is transmitted from person to person through air via droplets of respiratory secretions and direct contact with an infected person like oral contact with shared items.

Vitamin A has a major role in photo-transduction. Its deficiency causes night blindness in humans. Xerophthalmia, keratomalacia can also occur with its deficiency. Green, yellow-orange-red (dark- coloured) fruits and vegetables, eggs, milk; fortified cereals are rich source of vitamin A. Their avoidance over a long period may cause the vit-A deficiency symptoms.

The blood goes through the heart of fishes only once during one cycle of passage through the body, whereas in other vertebrates it goes twice through the heart during each cycle.

Concave mirrors are used for many purposes. Doctors use concave mirrors for examining eyes, ears, nose and throat. Concave mirrors are also used by dentists to see an enlarged image of the teeth. The reflectors of torches, headlights of cars and scooters are concave in shape. Convex mirror is used as side mirrors in automobiles. Convex mirrors can form images of objects spread over a large area. So, these help the drivers to see the traffic behind them.

It is composed of a mixture of sodium hydrogen carbonate and mild acid like tartaric acid.

Calcium phosphate Ca3(PO4)2 is a basic salt, as it is formed by the combination of a weak acid (phosphoric acid) and a slightly stronger base (calcium hydroxide).
3Ca(OH)2 + 2H3PO4 → Ca3(PO4)2 + 6H₂O

When a ray of light approaches a smooth polished surface and the light ray bounces back, it is called the reflection of light. The incident light ray which lands upon the surface is said to be reflected off the surface. The ray that bounces back is called the reflected ray. If a perpendicular were to be drawn on reflecting surface, it would be called normal. The figure below shows the reflection of an incident beam on a plane mirror. Image formation on a mirror is caused by reflection.
Refraction and diffraction have no role to play in it.

The way food is broken down in the human body, on reaction with oxygen, to give out energy; substances react with oxygen during combustion and give out heat and light.
The lowest temperature at which a substance catches fire is called its Ignition temperature. The ignition temperature of phosphorus is so low, that it catches fire in room temperature, in the presence of air.

The ratio of momentum and velocity of a substance gives mass.

Friction is defined as the force that opposes the motion of a solid object over another.
There are mainly four types of friction: static friction, sliding friction, rolling friction, and fluid friction.
Friction and normal force are directly proportional to the contacting surfaces and it doesn’t depend on the hardness of the contacting surface. With the increase in relative speeds, the sliding friction reduces whereas fluid friction increases with the increase in the relative speed, also fluid friction is dependent on the viscosity of the fluid.
Types of Friction
Following are the friction types which depend on the types of motion:
(1) Static Friction: The frictional force that acts between the surfaces when they are at rest with respect to each other. The magnitude of the static force is equal in the opposite direction when a small amount of force is applied. When the force increases, at some point maximum static friction is reached.
(2) Sliding Friction: The resistance that is created between any two objects when they are sliding against each other.
(3) Rolling Friction: The force which resists the motion of a ball or wheel and is the weakest types of friction.
(4) Fluid Friction: The friction that exists between the layers of the fluid when they are moving relative to each other.

During the development of a thunderstorm, the air currents move upward while the water droplets move downward. These vigorous movements cause separation of charges. By a process, the positive charges collect near the upper edges of the clouds and the negative charges accumulate near the lower edges. There is accumulation of positive charges near the ground also.
When the magnitude of the accumulated charges becomes very large, the air which is normally a poor conductor of electricity, is no longer able to resist their flow. Negative and positive charges meet, producing streaks of bright light and sound. We see streaks as lightning. The process of generation of lightning is called electric discharge. This can occur between two or more clouds; or between the clouds and earth. Lightning Conductor is a device used to protect buildings from the effect of lightning. A metallic rod, taller than the building, is installed in the walls of the building during its construction. One end of the rod is kept out in the air and the other is buried deep in the ground.
The rod provides easy route for the transfer of electric charge to the ground.

When the volume of an object changes, the volume, weight and mass of the object change, but the density remains the same.

The substances which vapourise on combustion, produce flame. The flame produced during the combustion of candle has three parts: non luminous zone, luminous zone and non-combustible zone. Unburnt carbon particles are present in the luminous zone of the flame.
The non-luminous zone of the candle flame has the highest temperature. It is the outermost region of the flame, which is blue in colour.

When an onion is cut, certain (lachrymator) compounds are released causing the nerves around the eyes (lacrimal glands) to become irritated. These compounds consist of methionine and cystine that are part of the amino acid family.

Hinge joints are found at the elbow and knee and they only allow movement in one direction or in only one plane. For instance, human fingers, toes, elbows, knees, and ankles contain hinge joints.

Small intestine is the principal organ for absorption of nutrients. Various enzymes are secreted into the small intestine which breaks down complex molecules into more simple molecules. Small intestine receives secretions from the liver (bile) and pancreas (pancreatic juice containing digestive enzymes).

The pituitary gland does not occur in pairs, while the adrenal gland, testis (in male) and ovary (in female) do.

Asexual propagation, sometimes referred to as vegetative propagation, involves taking vegetative parts of a plant (stems, roots, and/or leaves) and causing them to regenerate into a new plant or, in some cases, several plants. With few exceptions, the resulting plant is genetically identical to the parent plant.

Proteins make up hormones and enzymes. The formation of any particular protein is also controlled by a specific gene. Genes contain instructions for making proteins in a cell. The proteins that are produced could be enzymes that catalyze biochemical reactions. The enzyme is also in charge of the hormone production process. However, fat formation is not genetically determined.

There are some plants which do not have chlorophyll. They cannot synthesise food.
Like humans and animals such plants depend on the food produced by other plants. They use the heterotrophic mode of nutrition. For example: Cuscuta (Amarbel).Plants cannot absorb nitrogen in gaseous form. Soil has certain bacteria that convert gaseous nitrogen into a usable form and release it into the soil. This is absorbed by the plants along with water.

Sodium Azide is best known as the chemical found in automobile airbags. An electrical charge triggered by automobile impact causes sodium azide to explode and convert to nitrogen gas inside the airbag. Sodium azide is used as a chemical preservative in hospitals and laboratories.

Fluoride is essential in small quantities for the development of healthy teeth but causes mottling of the teeth if consumed in higher quantities.

Carbon, hydrogen and nitrogen were primarily responsible for the origin of life on the earth. It is believed that organic molecules could be formed by inorganic process under primitive earth conditions.

Due to high penetrating power, the properties of interference, diffraction and polarization are not possible in X-ray.

A passenger in a moving train tosses a coin upward which falls behind him. It implies that the motion of the train is accelerated. It happens because by the time the coin remains in the air, its velocity reduces and it falls behind the passenger.

Hypermetropia (Hyperopia) means far-sighted and it is where the image of a nearby object is formed behind the retina. This could be because the eye is too short or the cornea/crystalline lens does not refract light enough when trying to view an image. Concave lens is used to correct myopia and convex lens is used to correct hypermetropia.

Exothermic reactions are reactions or processes that release energy, usually in the form of heat or light. In an exothermic reaction, energy is released because the total energy of the products is less than the total energy of the reactants. For this reason, the change in enthalpy, for an exothermic reaction will always be negative. In the presence of water, a strong acid will dissociate quickly and release heat, so it is an exothermic reaction. Endothermic reactions are reactions that require external energy, usually in the form of heat, for the reaction to proceed.
Since endothermic reactions draw in heat from their surroundings, they tend to cause their environments to cool down. They are also generally non-spontaneous, since endothermic reactions yield products that are higher in energy than the reactants. As such, the change in enthalpy for an endothermic reaction is always positive. In order to melt the ice cube, heat is required, so the process is endothermic.

In order to see full image of a person, the minimum size of the mirror should be one half the person's height. This is so because, in reflection, the angle of incidence is equal to angle of reflection. So, to see the image of a 6 ft tall person, a 3 ft long mirror is required.

Porifera – Sponges
Coelenterata – Hydra, Jelly Fish
Platyhelminthes – Flat worm, Tape worm
Nematoda – Roundworms, hookworm

Lung is a major respiratory organ which regulates body temperature. During respiration, where one more energy is generated by the oxidation of food in the tissues of the body, on the other hand water vapour and gas are removed from the body through exhalation, as a result of which the body temperature is also controlled.

A mixture of Antimony Trisulphide and Potassium Chlorate is applied on the heads of matchsticks. Earlier, white phosphorus was also used along with these two chemicals, but due to its harmful effects, its use was discontinued in the manufacture of safety matches. The rubbing surface has powdered glass and a little red phosphorus. When the match is struck against the rubbing surface, some red phosphorus gets converted into white phosphorus. This immediately reacts with Potassium Chlorate in the matchstick head to produce enough heat to ignite Antimony Trisulphide and start the combustion.

Kidney stones are formed due to calcium oxalate. Mineral salts often collect in the pelvis of the kidney in the form of a mass, causing obstruction in the passage of urine.

The solution should be basic if it causes the red litmus test to turn blue. By adding an acid, its effects can be reversed. All are examples of base except hydrochloric acid (HCl).

Octopus belongs to Mollusca. Jellyfish belongs to Coelenterata. Silver fish belongs to Arthropoda. Bombay Duck belongs to Pisces.

Carbon-14 is radioactive isotope of carbon, which can mutate the DNA by getting incorporated into it. X-rays are high energy and ionizing rays.
These can cause mutation at genetic level though they generally damage the bio-molecules by altering their function. Coal miners have the risk to develop certain types of cancers.

Ptyalin digests the starch in the mouth. Pepsin is a proteolytic enzyme which breaks down the proteins into simple peptides. Renin is responsible for converting angiotensinogen to angiotensin.
Oxytocin is a hormone that stimulates the contraction of smooth muscles of the body.

Globulins are secreted by Lymphocytes and are known as antibodies. These antibodies help to fight against pathogens that attack the body.

Insulin is a fat-storage hormone that is released by the pancreas and regulates metabolic processes. Melatonin is produced by the pineal gland in the brain which controls sleep and wake cycles.

Washing soda – Na2CO3. 10H2O
Blue vitriol – CuSO4·5H2O
Baking Soda – NaHCO₃

Acid, any substance that in water solution tastes sour, changes the colour of certain indicators (e.g., reddens blue litmus paper), reacts with some metals (e.g., iron) toliberate hydrogen, reacts with bases to form salts, and promotes certain chemical reactions (acid catalysis). Examples of acids include the inorganic substances known as the mineral acids—sulfuric, nitric, hydrochloric, and phosphoric acids—and the organic compounds belonging to the carboxylic acid, sulfonic acid, and phenol groups. Acids may be identified as either strong or weak acids based on how completely they dissociate into their ions in water. A strong acid, such as hydrochloric acid, completely dissociates into its ions in water. A weak acid only partly dissociates into its ions, so the solution contains water, ions, and the acid (e.g., acetic acid).

The rusting of iron and steel can be prevented by various methods. Let's evaluate the options:
(A) Chromium Plating – Chromium plating can provide a protective layer that helps prevent rusting.
(B) Oiling and greasing – Applying oil or grease can create a barrier, preventing moisture and oxygen from reaching the metal surface, thereby inhibiting rusting.
(C) Plastic Coating – Plastic coating can act as a protective barrier, preventing direct contact between the metal and environmental factors that cause rust.
Therefore, the correct answer is (D). All three methods – Chromium plating, oiling and greasing, and plastic coating – can be effective in preventing rusting.

Since pollen grains are light, they can be carried by wind or water. Insects visit flowers and carry away pollen on their bodies. Some of the pollen lands on the stigma of a flower of the same kind. The transfer of pollen from the anther to the stigma of a flower is called pollination. If the pollen lands on the stigma of the same flower or another flower of the same plant, it is called self-pollination. When the pollen of a flower lands on the stigma of a flower of a different plant of the same kind, it is called cross-pollination.

The wire gets hot when an electric current passes through it. This is the heating effect of the electric current. Oersted observed the deflection of compass needle every time the current was passed through the wire. So, when electric current passes through a wire, it behaves like a magnet. This is the magnetic effect of the electric current.

A CT scan is a special type of X-ray test. Through this, an attempt is made to detect the malformations of the brain.

Algae called Chlorella and Spirulina are used as food by space travellers are they are rich in protein. Algae called Geladium and Gracilaria are used in making ice cream and jellies.

Incomplete combustion of fuels release Carbon Monoxide. It is a poisonous gas, which decreases the oxygen carrying capacity of blood. Chlorofluorocarbons, which are used in refrigerators, air conditioners and aerosol sprays, deplete the ozone layer of the atmosphere. After the Montreal protocol, nearly all the countries have started to use less harmful gases in the place of CFCs. Smoke contains oxides of nitrogen which combine with other air pollutants and fog to form smog. Sulphur Dioxide and Nitrogen Dioxide react with the water vapour present in the atmosphere to give sulphuric and nitric acid. This makes the rain acidic and is called acid rain.

In xerophytes the stomata open in night and remain closed during day as an adaptation to conserve water.
For example, CAM plants are desert succulents in which stomata opens at night time and carbon dioxide is fixed into organic acids, like malic acid and oxaloacetic acid.

When we are standing at a railway station and a train comes, we tend to fall towards the train. This can be explained using Bernoulli’s principle as the train goes past, the velocity of air between the train and us increases. Hence the pressure decreases. So, the pressure from behind pushes us towards the train.

Blood is the fluid which flows in blood vessels. It transports substances like digested food from the small intestine to the other parts of the body. It carries oxygen from the lungs to the cells of the body. It also transports waste for removal from the body.

10–24 m = Yocto
10–21 = Zepto
1021 = Zetta
1024 = Yotta
10–18 = Atto

Vitamins are complex organic compounds. Which control the actions of catalysts in metabolic reactions in the body. Animals get most of the vitamins from food as they are synthesized by plants.

Vitamin A deficiency causes an eye disease called night blindness.
Vitamin D deficiency causes rickets.
Deficiency of Vitamin C causes scurvy disease.
Vitamin B1 deficiency causes Beriberi.

The highest amount of protein is found in soybean. The amount of protein in it is up to 40%. This is mainly a pulse and oilseed crop. Milk is prepared from soybean, which is equivalent to cow's milk.

The metabolic process of fat gives more energy. Oxidation of 1 gram of fat releases 9.3 kcal of energy.

Some organisms live together and share both shelter and nutrients. This relationship is called symbiosis. For example, certain fungi live inside the roots of plants. The plants provide nutrients to the fungus and, in return, the fungus provides water and certain nutrients.
For example: lichens.The mode of nutrition in which organisms take in nutrients from dead and decaying matter is called saprotrophic nutrition. Such organisms with saprotrophic mode of nutrition are called saprotrophs. For example fungi, that grow on pickles, leather, clothes and other articles that had been left out in hot and humid weather for a long time, is a saprotroph. Note that during the rainy season such fungal growth may spoil a lot of household things.

The viscosity of plasma is dependent on the concentration of plasma proteins, such as fibrinogen, α1-globulins, α2-globulins, β-globulins, and γ-globulins.
Any elevation in the concentration of these proteins can cause plasma, and thus whole blood, viscosity to increase. White blood cells and platelets in the blood have no effect on its viscosity.

Antigens are those substances, which induce the formation of antibodies and activate the immune system. To destroy the viruses, fungi, or bacteria, the immune system creates antibodies that are specific for each antigen.

Eutrophication is the process by which the concentration of nutrients in a water body reaches high levels, especially phosphate and nitrate concentrations.

Cellulose is the most abundant organic material found in nature. It is a polysaccharide. Its purest form is cotton.

Lithotripsy is a medical procedure, in which with the help of rays, the patient is treated by breaking the stones located in kidney, gall bladder, bladder etc.

The process of transformation of water vapour into its liquid form is called condensation.
Tiny droplets of water on the surface of a glass containing ice are formed due to condensation.
Air contains water vapour, and when air comes in contact with a cold surface, the water vapour cools down and condenses to form droplets of water.
Evaporation and transpiration, both change water from liquid to vapour.

Excessive loss of fluid from the body is called dehydration. In this condition, electrolytes, mainly sodium chloride, are lost from the body.

Out of the above options, the brain of an ant is the largest in proportion to its body.

Plane mirrors are simply flat mirrors without curves. Because these can be found almost anywhere, the average person is incredibly familiar with them (even if they don't know the technical term). While the first manmade mirrors were made from intensely polished bronze, silver and other metals, today most mirrors are made from glass sheets finished with a thin layer of aluminum. That said, plane mirrors can be made from liquid as well: Gallium and mercury can be used for this purpose. Regardless of material construction, however, all flat mirrors function the same way. They reflect rays of light, producing an image. Characteristics of the image formed by a plane mirror:
It is virtual
It is erect and of same size as the object
The distance of object from the plane mirror is same as the distance of image from the plain mirror. One of the important characteristic of the image is that it is laterally inverted. It means if you raise your left hand it would appear in the plane mirror that you have raised your right hand.

Aqua Regia is a mixture of nitric acid and hydrochloric acid. It is a very corrosive acid and is used by goldsmiths while making jewellery.

Sperm and ovum, both are examples of single celled bodies. The fusion of both is called fertilization, the result of which is the formation of zygote. The cells of zygote divide continuously, to form a ball of cells, after which, the cells differentiate and divide into tissues and organs. This is called an embryo. The embryo undergoes development after being implanted on the wall of the uterus. The stage of embryo development, wherein all the body parts are distinguishable, is called foetus. Animals which give birth to offsprings, are called viviparous; and the ones which develop through eggs are called oviparous. Statement 2 is not correct, because fertilisation in some oviparous animals occurs outside the body, and in some, inside the body. Fertilisation in chicken is an example of internal fertilization. In many animals (frogs, toad, fish, starfish, etc), fertilization occurs outside the female body. In these animals, fertilization occurs in water. As soon as the egg is released from the female body, males release the sperms. All the sperms swim in the water with the help of their tail. These sperms, on coming in contact with the membrane of the egg, result in fertilization. This type of fertilization, where male and female gametes fuse outside the female body is called external fertilization.

Glycerol tri nitrate is also known as nitroglycerin. It is a heavy, colourless, oily explosive liquid. It is an essential ingredient of dynamite.

A tubelight consists of a long glass tube whose inner walls are phosphor coated. The inside of the tube is filled with an inert gas such as argon along with mercury vapor.

Cyclotron is such an accelerated device by which high velocities are generated in protons, alpha particles etc.

It is the microscopic unicellular organism found in pond water which keeps changing its shape and position constantly. It has a cell membrane, a rounded, dense nucleus and many small bubble-like vacuoles in its cytoplasm. The amoeba is a tiny, one-celled organism. You need a microscope to see most amoebas – the largest are only about 1 mm across. Amoebas live in fresh water (like puddle and ponds), in salt water, in wet soil, and in animals (including people). There are many different types of amoebas. The name amoeba comes from the Greek word amoibe, which means change. (Amoeba is sometimes spelled ameba.)
(1) Cell membrane – the thin layer of protein and fat that surrounds the amoeba; it allows some substances to pass into the cell, and blocks other substances.
(2) Contractile vacuole – a cavity within the amoeba that excretes excess water and waste; the waste is brought to the cell membrane and is then eliminated from the amoeba.
(3) Cytoplasm (ectoplasm and endoplasm) – a jelly-like material that fills most of the cell; the organelles (like the nucleus) are surrounded by cytoplasm.
(4) Food vacuole – a cavity within the amoeba in which food is digested (broken down in order to be absorbed by the amoeba).
(5) Nucleus – the major organelle of the amoeba, located centrally; it controls reproduction (it contains the chromosomes) and many other important functions (including eating and growth).
(6) Pseudopods – temporary “feet” that the amoeba uses to move around and to engulf food.
An amoeba consists of a single blobby cell surrounded by a porous cell membrane. The amoeba “breathes” using this membrane – oxygen gas from the water passes in to the amoeba through the cell membrane and carbon dioxide gas leaves through it. A complex, jelly-like series of folded membranes called cytoplasm fills most of the cell. A large, disk-shaped nucleus within the amoeba controls the growth and reproduction of the amoeba.

Solder, which is an alloy of lead and tin, is used to join electrical wires together.

Wind power is the conversion of the kinetic energy of the air into electrical energy. The energy generated from the flowing air is called wind energy.

Digestive juices convert complex substances of food into simpler ones. The digestive tract and the associated glands together constitute the digestive system.
The inner walls of the stomach and the small intestine, and the various glands associated with the alimentary canal such as salivary glands, the liver and the pancreas secrete digestive juices.

When a bullet is fired from a gun, the shoulder moves backwards, when jumping from a boat, the boat moves backwards, when you hit someone and you feel hurt, etc. are due to Newton's third law of motion. This is called the action-reaction law.

The liver is an abdominal glandular organ in the digestive system. It is located in the right upper quadrant of the abdomen, under the diaphragm and on top of the stomach. The liver is a vital organ that supports nearly every other organ to some capacity. The liver is the body's second-largest organ (skin is the largest organ).
Function: “The liver has a complex role in the function of the body,” said Jordan Knowlton, an advanced registered nurse practitioner at the University of Florida Health Shands Hospital.
“Detoxification, metabolism (including regulation of glycogen storage), hormone regulation, protein synthesis, digestion, and decomposition of red blood cells, to name a few.”
Production of bile, which helps carry away waste and break down fats in the small intestine during digestion.
Production of certain proteins for blood plasma.
Production of cholesterol and special proteins to help carry fats through the body
Conversion of excess glucose into glycogen for storage (glycogen can later be converted back to glucose for energy) and to balance and make glucose as needed
Regulation of blood levels of amino acids, which form the building blocks of proteins
Processing of hemoglobin for use of its iron content (the liver stores iron)
Conversion of poisonous ammonia to urea (urea is an end product of protein metabolism and is excreted in the urine)
Clearing the blood of drugs and other poisonous substances
Regulating blood clotting
Resisting infections by making immune factors and removing bacteria from the bloodstream
Clearance of bilirubin, also from red blood cells. If there is an accumulation of bilirubin, the skin and eyes turn yellow.

Carbon tetrachloride is used in firefighting.
▪️ Ethyl mercaptan is used to detect the leakage of LPG gas.
▪️ Iodoform and Gamoxygen are used as insecticides.
▪️ Aspirin is used as an antipyretic and analgesic.

When a bottle is filled with water and allowed to freeze, the bottle breaks because water expands on freezing.
When water becomes ice, its volume increases and density decreases, while on melting, the volume decreases while the density increases.

There is a symbiotic relationship between algae and fungus. For example, in organisms called lichens, a chlorophyll-containing partner, which is an alga, and a fungus live together. The fungus provides shelter, water and minerals to the alga and, in return, the alga prepares and provides food to the fungus.The bacterium called Rhizobium can take atmospheric nitrogen and convert it into a usable form. But Rhizobium cannot make its own food.
So, it often lives in the roots of gram, peas, moong, beans and other legumes and provides them with nitrogen. In return, the plants provide food and shelter to the bacteria. They, thus, have a symbiotic relationship. (i.e., between plants and bacteria).

Both carbohydrate and oxygen are formed in the process of photosynthesis.Besides leaves, photosynthesis also takes place in other green parts of the plant — in green stems and green branches. Desert plants have scales or spine-like leaves to reduce loss of water by transpiration. These plants have green stems which carry out photosynthesis.

Photoelectric device means which uses the photoelectric effect, in other words, which produces electricity/electric signal from light.
A photovoltaic cell is one such device. Other devices in the option are exactly the opposite of this, in other words, they produce light on the flow of electricity.
Photovoltaic cell:
A photovoltaic panel usually referred to as a module, is a structure made up of connected unique cells that produce an electric current when exposed to sunlight.
An electric field is produced when the cells are exposed to the sun.
Photovoltaic cells or commonly known as solar cells have vast use in digital technology.
For example entire satellite communication depends on it since this is the main source of power for it.
Photodiodes are used to accurately measure light intensity.
The photodiode works on the concept that an electric current begins to flow through it when the junction of this two-terminal semiconductor device is lit.
Photodiodes are utilized in CD players, smoke detectors, medical equipment, and the receivers for infrared remote controls used to operate everything from air conditioners to televisions.
Photodiodes all are used in photoelectric devices according to the requirements.
Devices like cameras, medical equipment, automobiles, and in many other applications.
A substance that emits photoemitted electrons when illuminated.
Emitting photons, particularly from metallic surfaces.

When breakdown of glucose occurs with the use of oxygen, it is called aerobic respiration; whereas food can also be broken down, without using oxygen. This is called anaerobic respiration.

Yeast is a unicellular organism in which reproduction is done through budding.The small bulb-like projection coming out from the yeast cell is called a bud. The bud gradually grows and gets detached from the parent cell and forms a new yeast cell. The new yeast cell grows, matures and produces more yeast cells.
The process of reproduction in algae is done by fragmentation. In this process, the algae (such as spirogyra) breaks up into two or more fragments. These fragments or pieces grow into new individuals.
Plants such as moss and ferns, also reproduce by means of spores. When spores are released they keep floating in the air reaching long distances. Under favourable conditions, a spore germinates and develops into a new individual.

(1) The image formed by a convex lens is real, inverted, and can be either larger, smaller, or the same size as the object, depending on the object's position relative to the focal point. So, the first assertion is not always correct.
(2) The image formed by a concave lens is virtual, erect, and smaller than the object. This is generally correct for concave lenses.
Therefore, the correct answer is (B) 2 only.

Water cools the combustible and the water vapours formed also surround the combustible material, cutting off the supply of air. thus, the fire is extinguished. The most common fire extinguisher is water. But for fires involving electrical equipment and inflammable materials like petrol, carbon dioxide (CO2) is the best extinguisher. CO2, being heavier than oxygen, covers the fire like a blanket. Since the contact between the fuel and oxygen is cut off, the fire is controlled. It does not harm the electrical equipment.CO2 can be stored at high pressure as a liquid in cylinders.
When released from the cylinder, CO2 expands enormously in volume and cools down.
Another way to get CO2 is to release a lot of dry powder of chemicals like sodium bicarbonate (baking soda) or potassium bicarbonate. On coming near the fire, these chemicals decompose to give off CO2.