# General Science practice questions (Group 4)

> This page has practice questions on General Science for the Group 4 / VAO (Combined Civil Services Examination-IV) exam, 20 in all: new questions our editors prepared and the founder approved, not previous-year questions. Tap “Answer and explanation” under each question for the correct answer and a short, sourced explanation. For previous-year papers and official answer keys, see tnpsc.gov.in.

Last updated: 2026-10-27 · By TNPSC Guide editorial team
URL: https://www.tnpscguide.com/exams/group-4/questions/gs-science

### Question 1

Assertion [A]: Vehicles are fitted with springs and shock absorbers.
Reason [R]: When the time of impact increases, the impulsive force decreases.

- A. [A] is true but [R] is false
- B. Both [A] and [R] are true and [R] is the correct explanation of [A]
- C. [A] is false but [R] is true
- D. Both [A] and [R] are true but [R] is not the correct explanation of [A]

Correct answer: B. Both [A] and [R] are true and [R] is the correct explanation of [A]

A longer time of impact lowers the impulsive force, which is why vehicles have springs and shock absorbers; [R] explains [A].

Source: அறிவியல், பத்தாம் வகுப்பு, தமிழ் வழி (Science, Standard X, Tamil medium; Samacheer Kalvi) (அலகு 1 இயக்க விதிகள், p. 7 (PDF p. 15))

### Question 2

Which of the following is not one of the types of inertia the textbook names?

- A. Inertia of mass
- B. Inertia of rest
- C. Inertia of motion
- D. Inertia of direction

Correct answer: A. Inertia of mass

Inertia is of three types, of rest, of motion and of direction; 'inertia of mass' is not one of them.

Source: அறிவியல், பத்தாம் வகுப்பு, தமிழ் வழி (Science, Standard X, Tamil medium; Samacheer Kalvi) (அலகு 1 இயக்க விதிகள், p. 11 (PDF p. 19))

### Question 3

Which quantity equals the product of the mass and the velocity of a moving body?

- A. Impulse
- B. Weight
- C. Inertia
- D. Momentum

Correct answer: D. Momentum

Momentum = mass × velocity of the moving body.

Source: அறிவியல், பத்தாம் வகுப்பு, தமிழ் வழி (Science, Standard X, Tamil medium; Samacheer Kalvi) (அலகு 1 இயக்க விதிகள், p. 11 (PDF p. 19))

### Question 4

Flying of a bird, swimming and the backward movement of a gun are examples of which of Newton's laws of motion?

- A. The first law of motion
- B. The second law of motion
- C. The third law of motion
- D. The law of gravitation

Correct answer: C. The third law of motion

Flying, swimming and the recoil of a gun illustrate the third law: every force has an equal and opposite force.

Source: அறிவியல், பத்தாம் வகுப்பு, தமிழ் வழி (Science, Standard X, Tamil medium; Samacheer Kalvi) (அலகு 1 இயக்க விதிகள், p. 7 (PDF p. 15))

### Question 5

Which of the following is an example of isotones?

- A. ₆C¹³, ₇N¹⁴
- B. ₁₇Cl³⁵, ₁₇Cl³⁷
- C. ₁₈Ar⁴⁰, ₂₀Ca⁴⁰
- D. ₇N¹⁴, ₁₇Cl³⁵

Correct answer: A. ₆C¹³, ₇N¹⁴

Isotones have the same number of neutrons: ₆C¹³ has 13 − 6 = 7 and ₇N¹⁴ has 14 − 7 = 7.

Source: அறிவியல், பத்தாம் வகுப்பு, தமிழ் வழி (Science, Standard X, Tamil medium; Samacheer Kalvi) (அலகு 7 அணுக்களும் மூலக்கூறுகளும், p. 101 (PDF p. 109))

### Question 6

According to the textbook, what is the value of the Avogadro number?

- A. 6.023 × 10²³
- B. 6.023 × 10⁻²³
- C. 22.4
- D. 273.15

Correct answer: A. 6.023 × 10²³

The Avogadro number, named after the Italian scientist Avogadro, is 6.023 × 10²³.

Source: அறிவியல், பத்தாம் வகுப்பு, தமிழ் வழி (Science, Standard X, Tamil medium; Samacheer Kalvi) (அலகு 7 அணுக்களும் மூலக்கூறுகளும், p. 96 (PDF p. 104))

### Question 7

By the modern periodic law, the physical and chemical properties of elements depend on what?

- A. Atomic mass
- B. Number of neutrons
- C. Vapour density
- D. Atomic number

Correct answer: D. Atomic number

The modern periodic law: the physical and chemical properties of elements depend on their atomic numbers.

Source: அறிவியல், பத்தாம் வகுப்பு, தமிழ் வழி (Science, Standard X, Tamil medium; Samacheer Kalvi) (அலகு 8 தனிமங்களின் ஆவர்த்தன வகைப்பாடு, p. 105 (PDF p. 113))

### Question 8

What are the elements of group 17 of the modern periodic table called?

- A. Noble gases
- B. The chalcogen family
- C. Halogens
- D. Alkali metals

Correct answer: C. Halogens

Group 17 is the halogens, group 18 the noble gases, group 16 the oxygen (chalcogen) family and group 1 the alkali metals.

Source: அறிவியல், பத்தாம் வகுப்பு, தமிழ் வழி (Science, Standard X, Tamil medium; Samacheer Kalvi) (அலகு 8 தனிமங்களின் ஆவர்த்தன வகைப்பாடு, p. 105 (PDF p. 113))

### Question 9

What is the dental formula of the rabbit?

- A. 2023/1023
- B. 2033/1023
- C. 2133/1023
- D. 2033/1033

Correct answer: B. 2033/1023

The rabbit's dental formula is I 2/1, C 0/0, PM 3/2, M 3/3, that is 2033/1023; it has no canines.

Source: அறிவியல், பத்தாம் வகுப்பு, தமிழ் வழி (Science, Standard X, Tamil medium; Samacheer Kalvi) (அலகு 13 உயிரினங்களின் அமைப்பு நிலைகள், p. 191 (PDF p. 199))

### Question 10

Which of these is not one of the kingdoms of the five-kingdom classification?

- A. Monera
- B. Viruses
- C. Protista
- D. Fungi

Correct answer: B. Viruses

The five kingdoms are Monera, Protista, Fungi, Plantae and Animalia; viruses are not among them.

Source: அறிவியல், ஒன்பதாம் வகுப்பு, தமிழ் வழி (Science, Standard IX, Tamil medium; Samacheer Kalvi) (அலகு 17 விலங்குலகம், p. 202 (PDF p. 206))

### Question 11

In binomial nomenclature, what does the first name, which begins with a capital letter, stand for?

- A. The species
- B. The kingdom
- C. The genus
- D. The family

Correct answer: C. The genus

In binomial nomenclature the first name is the genus, with a capital first letter; the second is the species, written in small letters.

Source: அறிவியல், ஒன்பதாம் வகுப்பு, தமிழ் வழி (Science, Standard IX, Tamil medium; Samacheer Kalvi) (அலகு 17 விலங்குலகம், p. 205 (PDF p. 209))

### Question 12

Which mineral works as the main component of haemoglobin?

- A. Iron
- B. Iodine
- C. Calcium
- D. Potassium

Correct answer: A. Iron

Among the minerals, iron works as the main component of haemoglobin; its lack causes anaemia.

Source: அறிவியல், ஒன்பதாம் வகுப்பு, தமிழ் வழி (Science, Standard IX, Tamil medium; Samacheer Kalvi) (அலகு 21 ஊட்டச்சத்து மற்றும் ஆரோக்கியம், p. 255 (PDF p. 259))

### Question 13

On a vernier caliper one smallest main-scale division is 0.5 mm and the vernier scale has 50 divisions in all. What is its least count?

- A. 0.1 mm
- B. 25 mm
- C. 0.01 mm
- D. 0.05 mm

Correct answer: C. 0.01 mm

Least count = value of one smallest main-scale division / total vernier divisions = 0.5 mm / 50 = 0.01 mm.

Source: அறிவியல், ஒன்பதாம் வகுப்பு, தமிழ் வழி (Science, Standard IX, Tamil medium; Samacheer Kalvi) (அலகு 1 அளவீடு, p. 5 (PDF p. 9))

### Question 14

Which instrument is used to measure the diameter of a thin wire or the thickness of a thin metal sheet?

- A. Barometer
- B. Lactometer
- C. Screw gauge
- D. Thermometer

Correct answer: C. Screw gauge

A screw gauge measures the diameter of a thin wire or the thickness of a thin metal sheet; it has a U-shaped metal frame.

Source: அறிவியல், ஒன்பதாம் வகுப்பு, தமிழ் வழி (Science, Standard IX, Tamil medium; Samacheer Kalvi) (அலகு 1 அளவீடு, p. 7 (PDF p. 11))

### Question 15

The hydrometer, which helps to find the relative density of a liquid, works on which principle?

- A. Pascal's law
- B. Kepler's laws
- C. Ohm's law
- D. Archimedes' principle

Correct answer: D. Archimedes' principle

A hydrometer finds the relative density of a liquid and works on Archimedes' principle, which the lactometer also uses.

Source: அறிவியல், ஒன்பதாம் வகுப்பு, தமிழ் வழி (Science, Standard IX, Tamil medium; Samacheer Kalvi) (அலகு 3 பாய்மங்கள், p. 36 (PDF p. 40))

### Question 16

On the Fahrenheit scale, what is the freezing point?

- A. 32°F
- B. 0°F
- C. 212°F
- D. 180°F

Correct answer: A. 32°F

On the Fahrenheit scale 32°F is the freezing point and 212°F the steam point, 180 parts apart; on the Celsius scale they are 0°C and 100°C, 100 parts apart.

Source: அறிவியல், ஒன்பதாம் வகுப்பு, தமிழ் வழி (Science, Standard IX, Tamil medium; Samacheer Kalvi) (அலகு 7 வெப்பம், p. 84 (PDF p. 88))

### Question 17

The ban the Chipko movement won in 1980 forbade felling forests in the Himalayan regions for how many years?

- A. 10 years
- B. 15 years
- C. 20 years
- D. 25 years

Correct answer: B. 15 years

The Chipko movement won its greatest success in 1980, a ban on felling forests in the Himalayan regions for 15 years.

Source: அறிவியல், பத்தாம் வகுப்பு, தமிழ் வழி (Science, Standard X, Tamil medium; Samacheer Kalvi) (அலகு 22 சுற்றுச்சூழல் மேலாண்மை, p. 316 (PDF p. 324))

### Question 18

Which of the following is a non-renewable resource?

- A. Forests
- B. Groundwater
- C. Petroleum
- D. Solar energy

Correct answer: C. Petroleum

Forests, crops, wildlife, groundwater, air and solar energy are renewable; minerals, coal and petroleum are non-renewable.

Source: அறிவியல், பத்தாம் வகுப்பு, தமிழ் வழி (Science, Standard X, Tamil medium; Samacheer Kalvi) (அலகு 22 சுற்றுச்சூழல் மேலாண்மை, p. 315 (PDF p. 323))

### Question 19

What are also called 'carbon sinks' because they hold carbon?

- A. Forests
- B. Fossil fuels
- C. Farm ponds
- D. Tides

Correct answer: A. Forests

Forests hold carbon, so they are also called carbon sinks.

Source: அறிவியல், பத்தாம் வகுப்பு, தமிழ் வழி (Science, Standard X, Tamil medium; Samacheer Kalvi) (அலகு 22 சுற்றுச்சூழல் மேலாண்மை, p. 316 (PDF p. 324))

### Question 20

What does the word 'Chipko' mean?

- A. To protect
- B. To plant
- C. To cut
- D. To hug

Correct answer: D. To hug

Chipko, the non-violent movement begun in 1973 to protect trees and forests, means 'to hug'.

Source: அறிவியல், பத்தாம் வகுப்பு, தமிழ் வழி (Science, Standard X, Tamil medium; Samacheer Kalvi) (அலகு 22 சுற்றுச்சூழல் மேலாண்மை, p. 316 (PDF p. 324))

## Sources

- [Official syllabus page](https://www.tnpsc.gov.in/english/syllabus.html)
- [Notifications](https://www.tnpsc.gov.in/English/Notification.aspx)