Answer: (b) 7

Explanation: H₂O is the chemical formula of water. The water is neither acid nor base. Water is only neutral. This category belongs to pH 7. Therefore, the pH of water is 7.

Answer: (d) Hydrogen

Explanation: In the reduction process, oxygen is added, and hydrogen is reduced from the reactant.

Answer: (c) Alcohol

Explanation: Alcohol is mainly used in hand sanitizers. It kills germs present on our hands or any other places by rendering their oxygen supply.

Answer: (c) Hertz

Explanation: The frequency is equal to the number of cycles per unit time, so its S.I unit is s^-1 which is equal to hertz. Therefore, the S.I unit of frequency is hertz.

Answer: (c) Red

Explanation: The acid turns blue litmus paper into red litmus paper, and the base turns red litmus paper into blue litmus paper.

Answer: (d) Trypsin

Explanation: There are three enzymes present in our stomach pepsin, hydrochloric acid, mucus. Trypsin is present in the small intestine. So, option (d) is the correct answer.

Answer: (d) Salivary

Explanation: The salivary gland is present in the human mouth, which secretes saliva to excrete fat present in human foods.

Answer: (a) Adrenal

Explanation: Adrenal gland is present above our kidneys. It controls our blood pressure. It also controls changes that occur in our body during the angry and happy mood.

Answer: (b)

Explanation: The basic unit of our neural system is the neuron. It connects our brain to all parts of our body.

Answer: (c) Nephron

Explanation: The basic unit of the excretory system is the nephron. It helps filter blood through urea. It is connected to human’s arteries and veins.

Answer: (d) Meter

Explanation: The wavelength is the distance between two consecutive waves. The distance is measured in meters, centimeters, or nanometers. Therefore, the unit of wavelength is meter, centimeter, or nanometer.

Answer: (a) 4 * 10¹⁴ to 8 * 10¹⁴

Explanation: White light has seven colors which are violet, indigo, blue, green, yellow, orange, red. There is a range of frequency of white light, and its frequency range is 4 * 10¹⁴ to 8 * 10¹⁴.

Answer: (d) yellow

Explanation: The AgBr is the chemical formula of the silver bromide. The color of AgBr is yellow.

Answer: (c) Law of inertia

Explanation: Newton’s first law of motion is also known as the law of inertia. It states that everyone remains in their previous position.

Answer: (a) Force

Explanation: According to newton’s second law of motion, change in momentum per unit time is equal to force applied on that body. Therefore, option (a) is the correct answer.

Answer: (c) Colorless

Explanation: SO₂ is the chemical formula of sulfur dioxide. The color of SO₂ gas is colorless. It gives a pungent smell. Therefore, if we want to recognize the presence of SO₂ gas, we smell it.

Answer: (d) White

Explanation: CuSO4 is the chemical formula of copper sulphate, and its color is white.

Answer: (a) Coulomb

Explanation: The S.I unit of electric charge is the coulomb.

Answer: (b) 7

Explanation: Heptane is a hydrocarbon chain that has seven carbon atoms. Therefore, option (b) is the correct answer.

Answer: (a) C6H6

Explanation: Benzene is a cyclic hydrocarbon chain. It has 6 carbon atoms which are alternatively connected with a double bond. Therefore, the chemical formula of benzene is C₆H₆.

Answer: (d) 15

Explanation: The atomic number of phosphorus is 15. It belongs to the 15th group and the 3rd period in the periodic table.

Answer: (c) Atomic size

Explanation: When we move from top to bottom in the periodic table, the number of shells increases, which increases the size of the atom.

Answer: (a) 0 – 7

Explanation: The total range of the PH scale is 0 to 14, in which the pH range of acids is 0 to 7.

Answer: (b) Diamond

Explanation: Diamond is a non-metal but still has high melting and boiling point due to its covalent structure. In these options, all other options are metals. Therefore, option (b) is the correct answer.

Answer: (a) Gold

Explanation: Gold and platinum are the most ductile metal. Ductility is the property of any element by which it can modify into a wire.

Answer: (b) Ampere

Explanation: The S.I unit of charge is ampere. One ampere is equal to the amount of current flowing across a unit length wire.

Answer: (a) Volt

Explanation: The S.I unit of potential difference is volt. One volt is equal to the potential difference across a wire having 1-ampere current apply 1-ohm resistance.

Answer: (b) Arteries

Explanation: The arteries are attached to the heart. They carry oxygen-rich blood from the heart to other parts of the body.

Answer: (d) Lungs

Explanation: The coronavirus has the most impact on human lungs. It causes difficulty in breathing and is harmful to health.

Answer: (a) Cornea

Explanation: The part of the eye on which the image is formed is the cornea. Image is focused by the lens on the cornea, which sends it to the brain through optical nerves.

Answer: (c) Rabies

Explanation: Rabies is the name of the disease caused by dog bites. In this disease, the person loses his ability to think and understand.

Answer: (d) Barometer

Explanation: The barometer is used for measuring air pressure. It is also called barometric pressure. It measures pressure in bar unit.

Answer: (a) Magnetic induction

Explanation: The basic principle of the electric generator is magnetic induction. It is given by faraday.

Answer: (c) Diopter

Explanation: The S.I unit of lens power is a diopter. It is equal to the reciprocal of the focal length of the lens. P = 1/F.

Answer: (b) Ohm

Explanation: The S.I unit of resistance is the ohm. If we apply 1 unit voltage in a wire and it gives 1-ampere current, then resistance across this wire is 1 ohm.

Answer: (a) C₂H₅OH

Explanation: The chemical formula of alcohol is C₂H₅OH. It is ethane with an alcohol group. It is also called ethanol.

Answer: (c) Bile juice

Explanation: Bile juice is secreted from the gall bladder. It is basic in nature. It helps neutralize acidic food.

Answer: (c) Homo sapiens

Explanation: The scientific name of humans is homo sapiens.

Answer: (a) Anura

Explanation: The scientific name of the frog is Anura.

Answer: (c) Poultry culture

Explanation: Poultry culture is the farming of hens. It is used for producing eggs. Pisci culture is the farming of fishes. Apiculture is the farming of bees.

Answer: (b) Wilhelm roentgen

Explanation: Wilhelm roentgen discovered the x-ray in 1895. X-ray is used in human body scanning.

Answer: (b) Henri Becquerel

Explanation: Henri Becquerel discovered the radioactivity.

Answer: (d) Respiration

Explanation: Respiration is the process by which a person breathes. In this process, oxygen is taken in, and carbon dioxide is taken out.

Answer: (b) Small intestine

Explanation: The small intestine is the organ of the human body where complete digestion of food like carbohydrates, proteins, and fats takes place.

Answer: (a) Sodium

Explanation: Sodium is a metal that is easily cut by a simple knife. Sodium is an alkali metal that belongs to the first group.

Answer: (d) Kevlar

Explanation: Kevlar is used in making bulletproof jackets.

Kevlar is a resistor of heat. It is a strong fabric, so it is used in bulletproof jackets.

Answer: (a) Newton

Explanation: Force is equal to mass into acceleration. The S.I unit of mass is the kilogram, and the S.I unit of acceleration is ms². So, the S.I unit of force is kgms² which is equal to Newton. Hence the S.I unit of force is Newton.

Answer: (a) Mangifera indica

Explanation: The scientific name of mango is Mangifera indica.

Answer: (b) Plant

Explanation: Plants use the sun’s energy for producing their food. So, they are the primary producer of our ecosystem.