Welcome to this General Science MCQ practice test designed for TNPSC aspirants. This quiz covers important General Science questions commonly asked in the TNPSC Exam, helping you strengthen your concepts and improve your problem-solving skills. Attempt each question carefully and check the explanations to build a solid foundation for your exam preparation.
Note: After completing the test, review the detailed explanations below to reinforce your knowledge and identify areas that need more attention.
General Science MCQ Quiz 2 – Key Points & Quick Revision
Reviewing every answer is one of the best ways to master General Science for the TNPSC Exam. The explanations below provide the correct answers with clear and concise reasoning, making it easier to understand important concepts and avoid similar mistakes in future General Science MCQ practice.
1. Human blood is?
Answer: Slightly alkaline
Explanation: Human blood normally has a pH of about 7.35–7.45, making it slightly alkaline. The pH of blood is carefully regulated by the lungs, kidneys, and chemical buffer systems in the body. Maintaining this narrow pH range is essential for enzymes, cells, and other body processes to function properly.
Why the other options are not suitable:
- Acidic: Acidic substances have a pH below 7, whereas normal human blood has a pH slightly above 7.
- Neutral: A neutral substance has a pH of 7, but normal human blood is slightly alkaline.
- Salty: Blood contains dissolved salts and other substances, but “salty” describes its composition or taste, not its pH.
2. Which organ pumps blood?
Answer: Heart
Explanation: The heart is a muscular organ that continuously pumps blood throughout the body. It sends oxygen-rich blood and nutrients to body tissues and helps transport carbon dioxide and other waste products away from them. The heart has four chambers that work together to maintain continuous blood circulation.
Why the other options are not suitable:
- Brain: The brain controls many body functions but does not pump blood.
- Liver: The liver performs important functions such as processing nutrients and detoxifying substances, but it does not pump blood.
- Lungs: The lungs exchange oxygen and carbon dioxide between the air and blood, but they do not pump blood.
3. Water boils at?
Answer: 100°C
Explanation: Water boils at 100°C under normal atmospheric pressure at sea level. At its boiling point, water changes from a liquid into water vapour. The boiling point can vary when atmospheric pressure changes, such as at higher altitudes.
Why the other options are not suitable:
- 50°C: Water normally remains in the liquid state at this temperature.
- 90°C: Water is hot at 90°C but normally has not yet reached its boiling point at sea level.
- 120°C: Water can reach temperatures above 100°C under increased pressure, but 120°C is not its normal boiling point.
4. Unit of electric current?
Answer: Ampere
Explanation: The SI unit of electric current is the ampere (A). Electric current refers to the rate at which electric charge flows through a conductor. One ampere means that one coulomb of electric charge flows through a point in a circuit in one second.
Why the other options are not suitable:
- Watt: Watt is the SI unit of electrical power.
- Volt: Volt is the SI unit of electric potential difference.
- Ohm: Ohm is the SI unit of electrical resistance.
4. Unit of electric current?
Answer: Ampere
Explanation: The SI unit of electric current is the ampere (A). Electric current is the rate at which electric charge flows through a conductor. One ampere means that one coulomb of electric charge flows through a point in a circuit in one second.
Why the other options are not suitable:
- Watt: Watt is the SI unit of electrical power.
- Volt: Volt is the SI unit of electric potential difference.
- Ohm: Ohm is the SI unit of electrical resistance.
5. Which gas is needed for respiration?
Answer: Oxygen
Explanation: Oxygen is needed for aerobic respiration, a process in which cells break down food such as glucose to release energy. The energy produced through respiration is used for various activities and functions of the body.
Why the other options are not suitable:
- Nitrogen: Nitrogen is present in large amounts in the atmosphere, but it is not directly used by humans for cellular respiration.
- Carbon dioxide: Carbon dioxide is mainly produced as a waste product during aerobic respiration and is removed from the body.
- Hydrogen: Hydrogen is not the gas required by humans for normal aerobic respiration.
6. Largest bone in human body?
Answer: Femur
Explanation: The femur, also known as the thigh bone, is the longest and strongest bone in the human body. It extends from the hip to the knee and plays an important role in supporting body weight and enabling movements such as walking, running, and standing.
Why the other options are not suitable:
- Skull: The skull protects the brain and forms the structure of the head, but it is not the largest bone.
- Rib: Ribs protect organs in the chest, including the heart and lungs, but they are much smaller than the femur.
- Arm: The arm contains bones such as the humerus, radius, and ulna, but none is the largest bone in the human body.
7. Plants prepare food by?
Answer: Photosynthesis
Explanation: Plants prepare their food through photosynthesis, mainly in the green parts of the plant. During this process, chlorophyll helps plants use sunlight to convert water and carbon dioxide into glucose, which serves as food. Oxygen is released as a by-product.
Why the other options are not suitable:
- Digestion: Digestion involves breaking down food into simpler substances and is not the process by which plants make their food.
- Respiration: Respiration releases energy from food; it does not produce food in plants.
- Transpiration: Transpiration is the loss of water vapour from plants, mainly through tiny openings called stomata.
8. Which vitamin is obtained through sunlight?
Answer: Vitamin D
Explanation: Vitamin D is produced in the body when the skin is exposed to ultraviolet (UVB) radiation from sunlight. The body then converts the vitamin D precursor into an active form that helps maintain healthy bones and teeth by supporting calcium absorption.
Why the other options are not suitable:
- Vitamin B: B vitamins are mainly obtained from foods such as grains, vegetables, dairy products, eggs, and meat.
- Vitamin A: Vitamin A is obtained mainly from foods such as dairy products, eggs, and vegetables containing beta-carotene.
- Vitamin C: Vitamin C is mainly obtained from fruits and vegetables such as oranges, guava, and tomatoes.
9. Force is measured in?
Answer: Newton
Explanation: The SI unit of force is the newton (N). Force is a push or pull that can change the motion, direction, or shape of an object. According to Newton’s second law, force is related to mass and acceleration by the equation F = ma.
Why the other options are not suitable:
- Watt: Watt is the SI unit of power.
- Joule: Joule is the SI unit of energy and work.
- Ampere: Ampere is the SI unit of electric current.
10. Which planet has rings?
Answer: Saturn
Explanation: Saturn is best known for its prominent ring system, which surrounds the planet. The rings are made mainly of countless particles of ice and rocky material, ranging from tiny grains to larger pieces. Saturn is a gas giant and has one of the most extensive and easily visible ring systems in the Solar System.
Why the other options are not suitable:
- Mars: Mars does not have a prominent ring system. It is a rocky planet with two small moons.
- Earth: Earth does not have a planetary ring system and has one natural satellite, the Moon.
- Venus: Venus does not have a ring system and is a rocky planet with no natural moons.
Final Revision Points
- Human blood → Slightly alkaline; normal blood pH is about 7.35–7.45.
- Organ that pumps blood → Heart; it circulates blood throughout the body.
- Boiling point of water → 100°C under normal atmospheric pressure.
- Unit of electric current → Ampere (A).
- Gas needed for aerobic respiration → Oxygen.
- Largest and strongest bone in the human body → Femur (thigh bone).
- Process by which plants prepare food → Photosynthesis.
- Vitamin produced with the help of sunlight → Vitamin D.
- SI unit of force → Newton (N).
- Planet with prominent rings → Saturn; its rings are mainly made of ice and rocky particles.
Further Reading
Strengthen your General Science fundamentals by exploring the official NCERT Science textbooks. These books explain core scientific concepts in a simple and systematic manner, making them an excellent resource for General Science MCQ practice and TNPSC Exam preparation.
or, if your quiz is based on Class 10 Science
Reviewing these important TNPSC questions can help strengthen your General Science knowledge across Biology, Physics, Chemistry, and basic science concepts. Use this Free Online Test as a quick revision tool and revisit the explanations whenever needed. Regular practice of TNPSC Science questions can improve your accuracy and confidence while preparing for the TNPSC exam.
