Biogas is produced from biomass by Anaerobic fermentation.

Refraction of light

CONCEPT

• Refraction of Light: The bending of the ray of light passing from one medium to the other medium is called refraction.

• The refraction of light takes place on going from one medium to another because the speed of light is different in the two media.
• The greater the differencein the speeds of light in the two media, the greater will bethe amount of refraction.
• A medium in which the speed of light is more is known as optically rarer medium and a medium in which the speed of light is less is known as an optically denser medium.

EXPLANATION

• A lemon kept in water in a glass tumbler appears to be bigger than its actual size when viewed from the sides. This is because of the refraction of light. Therefore option 3^rd is correct.
• Light is refracted as it passes from water into the air and as we know the refracted ray bends away from normal when it passes from denser to rarer medium.
• Water in a glass tumbler has a round outer surface that is convex and is a magnifying glass.
• As light is bent and being bent to the point that the object being observed appears to be larger than its normal size.

The urinary bladder

• The prostate gland is present below the urinary bladder.
• The prostate gland in male helps to control urination from the bladder.
• The prostate is a gland connected to the testicles at one end and the penis on the other end.
• While ejaculation the prostate stores semen and makes fluid which liquefies it before it ejects out of the penis.
• DIAGRAM

Potential energy

• The energy possessed by an object by its position or configuration is called Potential energy.
• Examples: climbing up on the chair and lifting heavy item to some height.

Plasma

• Plasma: The liquid component of blood which performs the function of transportation of food, carbon dioxide, nitrogenous waste.
• It transfers dissolved substances such as nutrients and electrolytes etc. It also carries blood components throughout the body.

Corrosion

• Corrosion causes damage to bridges, iron railings and all objects made of metals.
• Corrosion is a process where metals are attacked by moisture, acids etc.
• Corrosion is the black coating that develops on articles made of silver or the green coating on copper articles.

Corrosion

The speed of sound in air at 0°C is 331ms^-1 or around 1200 km per hour.

Speed of sound (m/s) = 331 + 0.60 T(°C)

Hence, the speed of sound in air at 0°C is 331ms^-1.

These plants have fibrous roots

• Fibrous roots is not a characteristic of dicotyledons plants.
• Its roots develop from radicle and the seed has two cotyledons or embryonic leaves.
• Their leaves have reticulate venation and have a pentamerous and tetramerous flower.
• Examples: mustard, bitter gourd, watermelon, brinjal, apple, mango, tamarind etc.

720m

Given:

A rocket is launched to travel vertically upward with a constant velocity of 20 m/s.

Concept used;

we know that S = ut

when it is moving at a constant velocity.

Calculation:

After 35 seconds the distance will be = S = 20 × 35

⇒ 700 m

Now from 700 m above the ground now it travels in a free fall.

The initial velocity = 20 m/s

Final velocity = 0

Acceleration due to gravity = -10

Now,

⇒ V² = U² + 2gs

⇒ 0 = 400 - 20S

⇒ 20s = 400

⇒ S = 400/20

⇒ S = 20 m

The height achieved = 700 + 20 = 720 m

∴ The required answer is 720 m.

Mendeleev

CONCEPT:

• Dmitri Mendeleev, the Russian chemist formulated a periodic law which states that the properties of elements are a periodic function of their atomic masses.

EXPLANATION

• Mendeleev was the most important contributor to the early development of the Periodic table.
• He categorised 63 elements on the basis of their physical and chemical properties in the increasing order of the atomic masses.
• Mendeleev’s periodic table was based on the mass number. This relation is known as "periodic law".

Additional Information

• Mendeleev's periodic table contains vertical columns called groups and horizontal rows called periods.
• He placed elements having similar properties in the same group. For example, Cobalt (atomic mass 58.9) was placed before nickel (atomic mass 58.7).
• He predicted the existence of certain elements that had not been discovered at that time and named them as Eka-Carbon, Eka-Aluminium, Eka-Silicon.

Methanoic acid

Key Points

CONCEPT:

• Nettle is an herbaceous plant that grows in the wild.
• Nettle leaves have stinging hair, which causes painful stings when touched accidentally. 
• This is due to the methanoic acid secreted by them. 
• A traditional remedy is rubbing the area with the leaf of the dock plant, which often grows beside the nettle.

Additional Information

Doppler effect

CONCEPT:

• Doppler Effect:
  • It works on both light and sound objects.
  • For instance, when a sound object moves towards you, the frequency of the sound waves increases, leading to a higher pitch.
  • Conversely, if it moves away from you, the frequency of the sound waves decreases, and the pitch comes down.

EXPLANATION

• Peltier effect:
  • The cooling of one junction and the heating of the other when the electric current is maintained in a circuit of material consisting of two dissimilar conductors, the effect is even stronger in circuits containing dissimilar semiconductors.
• Ultrasound Voice:
  • It is not a unique type of sound, therefore, but is classified differently due to the fact that humans can not hear it.
  • It has a frequency greater than 20 kHz, which is beyond the frequency limit of sounds that humans are able to hear.
• Subsonic effect:
  • The sound waves of frequencies less than the lower limit (i.e.,20 Hz) of the audible range are known as subsonic or infrasonic waves.
  • The human ear can perceive sound waves of frequency ranging from 20 Hz to 20 kHz.

Wavelength

CONCEPT:

• Sound is a wave that is produced by vibrations. 
• The vibrations are carried out in the form of waves. 
• The sound wave consists of continuous formation of high-pressure area and low-pressure area. 
• The high-pressure area is called compression and the low-pressure area is called rarefaction. 
• Sound produces vibrations in the medium of its propagation. So, sound requires a medium to travel. 

• The distance between two continuous compressions or rarefactions is called wavelength. 
• If one complete cycle of compression and rarefaction is completed we one oscillation has been completed. 

So, the correct option is the wavelength.

• The amplitude of the wave is the maximum distance the particle oscillating moves from the mean position.
• The frequency of the wave is the number of times one completes the cycle of compressions. SI unit of frequency is Hertz.
• The reciprocal of frequency is the time period.

Additional Information

• The number of vibrations at which sound waves travel per second is called the frequency of the sound wave.
• It is denoted by f or ν. 
• The SI unit of frequency is Hertz (Hz).
• The Hertz is the standard unit for measuring the frequency of a wave.
• One Hertz is equal to one cycle per second.
• Dimensional formula of frequency (f) = [M0L0T-1]
• Frequency is the number of occurrences of a repeating event per unit of time.
• It is also referred to as temporal frequency, which emphasizes the contrast between spatial frequency and angular frequency.
• Frequency is measured in units of hertz which is equal to one occurrence of a repeating event per second.
• The formula of Frequency is f = 1/T (f =frequency and T = Time period).

Four

Key Points

• Blood brings oxygen and nutrients to all the parts of the body so they can keep working.
• Plasma, Red blood cells,white blood cells, and platelets are the four fundamentals parts of human blood.
• The four main functions of blood are
  • ​Supplying tissues and cells with oxygen 
  • feeding the cells with critical nutrients like glucose, fatty acids, and amino acids.
  • eliminating waste products including urea, lactic acids and carbon dioxide.
  • while blood cells defend the body against illnesses, infections and foreign objects.
• Blood groups are complex chemical systems found on the surface of blood cells.
• There are four main blood groups (types of blood)– A, B, AB, and O.
• Blood group and Rh factor are discovered by Karl Landsteiner.
• Blood group without antigens– O.
• Blood group without antibody– AB.
• The blood group is known as the universal donor– O^- group.
• The blood group is known as the universal recipient - AB⁺ group.

Additional Information

• A very important fluid is human blood.
• No human can live without this fluid.
• The delivery of oxygen to various body parts is one of the most significant roles played by blood.
• Without blood, the body won't get any oxygen, which will cause death.
• Solid and liquids makes up the blood.
• Water, salts and protein make up the plasma's liquid component.
• Plasma make up most of the blood.
• Red blood cells, white blood cells and platelets make up the solid part of the blood.
• The oxygen from your lungs is transported to your tissues and organs by red blood cells (RBC).

Malachite

Key Points

• Malachite is a copper carbonate hydroxide mineral with the formula Cu₂CO₃(OH)₂.
• It is known for its green color and is used as a gemstone and pigment in paints.
• Malachite forms at shallow depths within the Earth's crust, typically in the oxidized zones of copper deposits.
• It is one of the most important ores of copper and has been mined for this metal since antiquity.

Additional Information

• Chromite
  • Chromite is an iron chromium oxide with the formula FeCr₂O₄.
  • It is the principal ore of chromium, a metal used to make stainless steel, nichrome, and chrome plating.
• Haematite
  • Haematite, also spelled hematite, is an iron oxide with the formula Fe₂O₃.
  • It is the most important ore of iron and is used to produce iron and steel.
• Magnetite
  • Magnetite is an iron oxide with the formula Fe₃O₄.
  • It is one of the main iron ores and is used in the production of iron and steel.

Gymnosperm

Key Points

• Gymnosperms are a group of plants that bear naked seeds.
• As in gymnosperms, the fertilized ovule becomes the seed but there is no ovary to bring about fruit formation. 
• The ovules are naked and directly borne on the cone.
• So they are called naked seeded plants.
• These plants develop on the surface of scales or leaves, or at the end of stalks forming a cone-like structure.
• They are usually perennial, evergreen and woody.
• Example:
  • pines and deodar.​

Additional Information

• Bryophyte
  • ​Bryophytes are the informal group name for mosses, liverworts, and hornworts.
  • They are non-vascular plants, which means they have no roots or vascular tissue, but instead absorb water and nutrients from the air through their surface (e.g., their leaves).
• ​Pteridophyte
  • A pteridophyte is a vascular plant (with xylem and phloem) that disperses spores.
  • Because pteridophytes produce neither flowers nor seeds, they are sometimes referred to as "cryptogams", meaning that their means of reproduction is hidden.
• Algae
  • ​Algae are defined as a group of predominantly aquatic, photosynthetic, and nucleus-bearing organisms that lack the true roots, stems, leaves, and specialized multicellular reproductive structures of plants.

middle ear

Key Points

• The human ears help in sensory functions like hearing and maintenance of body balance.
• The human ears can be anatomically divided into three major sections called the outer ear, the middle ear, and the inner ear.
• The middle ear contains three ossicles namely malleus, incus, and stapes.
• The malleus, incus, and stapes attached to one another in a chain-like fashion.
• The middle ear is an air-filled chamber.
• The smallest bone called stapes (or stirrup) found in the human body is located in the middle ear.
• Stapes is the smallest bone in the human body.
• The stapes is attached to the oval window of the cochlea.
• The malleus is attached to the tympanic membrane.

​

Additional Information

• The eustachian tube is the narrow tube that leads to the pharynx in the middle ear.
  • It helps in equalizing the pressures on either side of the eardrum.
• The outer ear consists of the pinna and external auditory canal.
• Helix is a prominent outer rim of the ear pinna.

Blood helps in sensory inputs.

Important Points

• Bone is the main connective tissue that provides the structural frame of the body.
• Bones support and protect softer tissues and organs.
• Blood is a fluid connective tissue containing plasma, red blood cells (RBC), white blood cells (WBC) and platelets.
• Blood protects the body from disease.
• It is the main circulating fluid that helps in the transport of various substances.
• Blood carries oxygen from the lungs to the other parts of the body.
• Blood carries carbon dioxide from the body cells to the lungs.
• But Blood does not help with sensory inputs.
  • So Statement 3 is the correct answer.