Question 1

Which metal is used in mobile phone batteries?

Accepted Answer

Correct Answer: Lithium

Explanation: Lithium is the key metal used in Lithium-ion batteries, which power smartphones, laptops, and electric vehicles. Lithium is the lightest metal and has a high electrochemical potential, allowing these batteries to store a lot of energy in a small, lightweight package. They are rechargeable and have a relatively long lifespan.

Question 2

What is the functional unit of the Kidney?

Accepted Answer

Correct Answer: Nephron

Explanation: The Nephron is the microscopic structural and functional unit of the kidney. Each kidney contains about a million nephrons. They filter blood, remove waste products and excess fluid to form urine, and reabsorb necessary nutrients back into the bloodstream. This process regulates blood pressure and electrolyte balance.

Question 3

Where does the digestion of protein start?

Accepted Answer

Correct Answer: Stomach

Explanation: Protein digestion begins in the Stomach. The stomach lining secretes hydrochloric acid and the enzyme pepsin, which break down long protein chains into smaller peptides. Digestion of carbohydrates starts in the mouth, but proteins remain intact until they reach the acidic environment of the stomach.

Question 4

Which planet is the hottest in the Solar System?

Accepted Answer

Correct Answer: Venus

Explanation: Although Mercury is closer to the Sun, Venus is the hottest planet. This is due to its thick atmosphere, composed mainly of carbon dioxide, which creates a runaway Greenhouse Effect. The atmosphere traps heat, raising surface temperatures to about 465°C, which is hot enough to melt lead. Mercury has no atmosphere to hold heat.

Question 5

The chemical used for 'Artificial Rain' or Cloud Seeding is:

Accepted Answer

Correct Answer: Silver Iodide

Explanation: Silver Iodide (AgI) is commonly used for cloud seeding to induce artificial rain. Its crystal structure is similar to that of ice. When released into clouds, it provides nuclei for water vapor to condense around, forming ice crystals that eventually melt and fall as rain. This technique is used to combat drought or clear fog from airports.

Question 6

What is the fourth state of matter?

Accepted Answer

Correct Answer: Plasma

Explanation: Plasma is considered the fourth state of matter, beyond solid, liquid, and gas. It consists of ionized gas with free-moving ions and electrons. It is actually the most common state of matter in the universe, making up stars (including our Sun) and lightning. On Earth, it is found in neon signs and plasma TV screens.

Question 7

Which gas is used for artificial ripening of green fruits?

Accepted Answer

Correct Answer: Ethylene (Ethene)

Explanation: Ethylene (also known as Ethene) is a plant hormone that triggers the ripening process. Commercially, fruits like bananas and mangoes are picked green and then exposed to ethylene gas in warehouses to ripen them just before sale. This ensures they don't spoil during transport. Calcium carbide is also used sometimes but is banned in many places due to health risks.

Question 8

Raindrops are spherical due to:

Accepted Answer

Correct Answer: Surface Tension

Explanation: Raindrops take a spherical shape due to Surface Tension. The water molecules on the surface are pulled inward by cohesive forces, trying to minimize the surface area. Since a sphere has the smallest surface area for a given volume, the droplet naturally forms a round shape. Air resistance may slightly flatten larger drops as they fall.

Question 9

Which is the largest gland in the human body?

Accepted Answer

Correct Answer: Liver

Explanation: The Liver is the largest internal organ and the largest gland in the human body. It performs over 500 vital functions, including detoxifying the blood, producing bile for digestion, and storing glycogen and vitamins. It has the unique ability to regenerate itself; even if a large part is removed, it can grow back to its full size.

Question 10

The mirrors used by dentists to examine teeth are:

Accepted Answer

Correct Answer: Concave Mirrors

Explanation: Dentists use Concave Mirrors because they produce a magnified and upright image of the teeth when held close. This allows the dentist to see details of cavities or cracks clearly. A convex mirror would make the image smaller, which is not useful for examination. Concave mirrors are also used in shaving mirrors and telescopes.

Question 11

What is the unit of frequency?

Accepted Answer

Correct Answer: Hertz

Explanation: The unit of frequency is the Hertz (Hz). One Hertz is defined as one cycle per second. It is named after Heinrich Hertz, who proved the existence of electromagnetic waves. It is used to measure everything from sound waves and radio frequencies to computer processor speeds (e.g., Gigahertz).

Question 12

Which acid is found in Apples?

Accepted Answer

Correct Answer: Malic Acid

Explanation: Apples contain Malic Acid, which contributes to their sour or tart taste. The word 'malic' is derived from the Latin word 'malum', meaning apple. This acid is also found in many other fruits like grapes and watermelons. It plays a role in the body's energy production cycle (Krebs cycle) and is sometimes used as a food additive.

Question 13

The deficiency of Vitamin D in children causes:

Accepted Answer

Correct Answer: Rickets

Explanation: Rickets is a condition that affects bone development in children, causing soft and weak bones. It is primarily caused by a prolonged deficiency of Vitamin D, which is essential for calcium absorption. Symptoms include bowed legs, stunted growth, and bone pain. Exposure to sunlight and consuming fortified foods can prevent it.

Question 14

Which instrument is used to measure Blood Pressure?

Accepted Answer

Correct Answer: Sphygmomanometer

Explanation: A Sphygmomanometer is the medical instrument used to measure blood pressure. It typically consists of an inflatable cuff, a measuring unit (mercury or aneroid gauge), and a mechanism for inflation. Doctors use it in conjunction with a stethoscope to listen to blood flow sounds. Normal blood pressure is typically around 120/80 mmHg.

Question 15

What is the normal pH of human blood?

Accepted Answer

Correct Answer: 7.35 - 7.45

Explanation: The normal pH of human blood is slightly alkaline, ranging from 7.35 to 7.45. The body maintains this pH range strictly because enzymes and cells require it to function correctly. If the pH drops below 7.35 (acidosis) or rises above 7.45 (alkalosis), it can lead to severe health complications and even death. The kidneys and lungs help regulate this balance.

Question 16

Lead pencils contain:

Accepted Answer

Correct Answer: Graphite

Explanation: Despite the name, 'lead' pencils do not contain any lead metal. The core is made of Graphite mixed with clay. Graphite is a form of carbon that is soft and leaves a mark on paper. The name 'lead' stuck because when graphite was first discovered, it was mistaken for a form of lead. It is non-toxic, unlike actual lead.

Question 17

Who discovered X-rays?

Accepted Answer

Correct Answer: Wilhelm Roentgen

Explanation: Wilhelm Roentgen, a German physicist, discovered X-rays in 1895. He found that these mysterious rays could pass through solid objects, including the human body, to create images of bones. He famously took an X-ray of his wife's hand, showing her wedding ring. For this discovery, he received the first-ever Nobel Prize in Physics in 1901.

Question 18

Which part of the brain controls the balance and posture of the body?

Accepted Answer

Correct Answer: Cerebellum

Explanation: The Cerebellum is the part of the brain located at the back of the skull. Its primary function is to coordinate voluntary movements such as posture, balance, coordination, and speech. While it does not initiate movement, it fine-tunes it to ensure smooth and balanced muscle activity. Damage to this area causes dizziness and loss of balance.

Question 19

The chemical name of Baking Soda is:

Accepted Answer

Correct Answer: Sodium Bicarbonate

Explanation: Baking Soda is chemically known as Sodium Bicarbonate (NaHCO3). It is a salt that breaks down to release carbon dioxide gas when heated or mixed with an acid (like vinegar or yogurt). This release of gas causes dough and batter to rise, making it a key ingredient in baking. It is also used as an antacid to treat heartburn.

Question 20

Which gas is used in balloons because it is lighter than air?

Accepted Answer

Correct Answer: Helium

Explanation: Helium is used in balloons and airships because it is much lighter than air and is non-flammable (unlike hydrogen). This low density allows the balloon to float upwards. It is the second most abundant element in the universe after hydrogen. Helium is also used in cooling MRI machines due to its extremely low boiling point.

Everyday Science MCQs