Explanation

• Comets: huge masses of snow and rocks that revolve around the Sun in orbits.
• Comets: have huge glowing tails.
• Halley's Comet was last seen in: 1986
• Halley's Comet will be next seen in: 2062

Last verified on 18-03-2026

Explanation

• Apollo 11 was the mission that successfully landed astronauts.
• Neil Armstrong and Buzz Aldrin on the moon on July 20, 1969.

Last verified on 15-03-2026

Explanation

• Security mirrors are typically convex mirrors.

The examples of concave mirrors:

• Cosmetic mirrors (makeup mirrors)
• Dentist mirrors
• Car headlight mirrors

Last verified on 18-03-2026

Explanation

• A kaleidoscope is an optical instrument that creates symmetrical, colorful multiple images using mirrors and colored objects.
• When rotated, it continuously forms new patterns of images.
• Commonly used for educational purposes and toys.

Last verified on 18-03-2026

Explanation

• Reflection occurs when light bounces back from a surface instead of passing through it.
• Shiny or smooth surfaces like mirrors produce clear and regular reflections.
• This principle is used in mirrors, periscopes, and optical instruments.

Last verified on 18-03-2026

Explanation

• Kinetic energy is the energy an object possesses due to its motion.
• Any moving object, such as a car, a ball, or a person, has kinetic energy.
• The amount of kinetic energy an object has depends on its mass and velocity.

Last verified on 18-03-2026

Explanation

• A saturated solution contains the maximum amount of solute that can dissolve at a given temperature.
• Any additional solute added will remain undissolved.
• Example: Sugar in water at room temperature reaches saturation when no more sugar dissolves.
• If a solution contains less solute than the maximum, it is called unsaturated.

Last verified on 18-03-2026

Explanation

• Nitrogen (N₂) makes up about 78% of Earth's atmosphere.
• It is a colorless, odorless, and inert gas, essential for life but not directly used in respiration.
  

Additional information:

Composition of Air – Approximate %:

• Nitrogen – 78%
• Oxygen – 21%
• Argon – 0.93%
• Carbon Dioxide – 0.04%
• Other trace gases (Neon, Helium, Methane, Krypton, etc.) – 0.03%

Last verified on 18-03-2026

Explanation

• Hydrogen is the lightest gas in the periodic table with atomic number 1.
• Its low density allows balloons to float in air.
• Used in party balloons, airships, and some scientific experiments.

Last verified on 18-03-2026

Explanation

• Sublimation is the process where a solid changes directly into gas without passing through the liquid state.
• It is used to purify solids that can vaporize easily, leaving impurities behind.
• Common examples include iodine, camphor, and naphthalene.

Last verified on 18-03-2026