CDS Physics and Science 1 — Questions and Answers
Question 1: What is Newton's second law of motion?
- Force equals mass times acceleration (F = ma) (Correct answer)
- Every action has an equal and opposite reaction
- An object at rest stays at rest
- Energy is conserved
Correct answer: Force equals mass times acceleration (F = ma)
Newton's second law states that force equals mass multiplied by acceleration: F = ma.
Question 2: What is the SI unit of electric current?
- Ampere (Correct answer)
- Volt
- Ohm
- Watt
Correct answer: Ampere
The Ampere (A) is the SI unit of electric current, defined as the flow of one coulomb per second.
Question 3: The speed of light in vacuum is approximately how many km/s?
- 300,000 km/s (Correct answer)
- 150,000 km/s
- 500,000 km/s
- 200,000 km/s
Correct answer: 300,000 km/s
The speed of light in vacuum is approximately 300,000 km/s (3 × 10⁸ m/s).
Question 4: Which gas is produced when zinc reacts with dilute sulphuric acid?
- Hydrogen (Correct answer)
- Oxygen
- Carbon dioxide
- Nitrogen
Correct answer: Hydrogen
When zinc reacts with dilute H₂SO₄, zinc sulphate and hydrogen gas are produced: Zn + H₂SO₄ → ZnSO₄ + H₂.
Question 5: What does DNA stand for?
- Deoxyribonucleic Acid (Correct answer)
- Diribonucleic Acid
- Deoxyribonitric Acid
- Dioxyribonucleic Acid
Correct answer: Deoxyribonucleic Acid
DNA stands for Deoxyribonucleic Acid, the molecule that carries genetic information in living organisms.
Question 6: Which phenomenon explains why the sky appears blue?
- Rayleigh Scattering (Correct answer)
- Reflection
- Refraction
- Diffraction
Correct answer: Rayleigh Scattering
Rayleigh Scattering causes shorter blue wavelengths of sunlight to scatter more than other colors, making the sky appear blue.
CDS Physics and Science 1
What is Newton's second law of motion?