N-Level Combined Science 1 — Questions and Answers
Question 1: What is the chemical symbol for water?
- WA
- H₂O (Correct answer)
- HO
- W₂O
Correct answer: H₂O
Water's chemical formula is H₂O — two hydrogen atoms bonded to one oxygen atom.
Question 2: What force keeps us on the ground?
- Magnetic force
- Friction
- Gravity (Correct answer)
- Tension
Correct answer: Gravity
Gravity is the force of attraction between all objects with mass. Earth's gravity pulls objects towards its centre, keeping us on the ground.
Question 3: Which organ pumps blood around the body?
- Lungs
- Kidneys
- Brain
- Heart (Correct answer)
Correct answer: Heart
The heart is a muscular pump that circulates blood around the body, delivering oxygen and nutrients to all organs and tissues.
Question 4: What gas do plants take in during photosynthesis?
- Oxygen
- Nitrogen
- Carbon dioxide (Correct answer)
- Hydrogen
Correct answer: Carbon dioxide
During photosynthesis, plants absorb carbon dioxide (CO₂) from the air and use it, along with water and sunlight, to produce glucose.
Question 5: What is the state of matter with no fixed shape and no fixed volume?
- Solid
- Liquid
- Gas (Correct answer)
- Plasma
Correct answer: Gas
A gas has no fixed shape and no fixed volume — it expands to fill any container. Its particles move rapidly and are far apart.
Question 6: Which colour of light has the shortest wavelength in the visible spectrum?
- Red
- Orange
- Green
- Violet (Correct answer)
Correct answer: Violet
In the visible spectrum, violet light has the shortest wavelength (highest frequency). Red has the longest wavelength (lowest frequency).
N-Level Combined Science 1
What is the chemical symbol for water?