Physics Chemistry & Biology Test 8
What is the chemical formula of water ?
  • CO2
  • H₂O
  • H2 D) 02
  • 02
Explanation: Water is made up of 2 atoms of hydrogen (H₂) and 1 atom of oxygen (O). Hence, its chemical formula is H₂O.
What is the speed of light in vacuum ?
  • 3×105 km/s
  • 3x10 m/s
  • 3×108 m/s
  • 30,000 km/s
Explanation: The speed of light in vacuum is approximately 3 × 10⁸ meters per second (m/s), which is equal to 3 lakh kilometers per second (3×10⁵ km/s). This is one of the fundamental constants of nature, denoted by the symbol ‘c’.
Which is the largest organ in the human body ?
  • Heart
  • Brain
  • Skin
  • Liver
Explanation: The skin is the largest organ of the human body. It covers the entire external surface and helps in — Protecting internal organs, Regulating body temperature, and Sensing touch, heat, and cold.
H₂SO₄ is the chemical formula of which acid ?
  • Hydrochloric acid
  • Sulphuric acid
  • Nitric acid
  • Carbonic acid
Explanation: H₂SO₄ represents Sulphuric acid, a strong acid widely used in industries. It is known as the “King of Chemicals” because it is used in manufacturing fertilizers, paints, detergents, and batteries.
Who discovered electricity ?
  • Newton
  • Faraday
  • Benjamin Franklin
  • Ohm
Explanation: Benjamin Franklin is credited with discovering electricity in the 18th century. He performed his famous kite experiment in 1752, proving that lightning is a form of electrical energy.
Which gas makes the Sun shine ?
  • Hydrogen
  • Helium
  • Oxygen
  • Nitrogen
  • Hydrogen
    • Explanation: The Sun shines because hydrogen gas undergoes nuclear fusion in its core — → Four hydrogen atoms combine to form one helium atom, releasing a huge amount of light and heat energy. This process is what makes the Sun glow brilliantly. ☀️