Explanation

• LED (Light Emitting Diode) is a semiconductor device that emits light when electric current passes through it.
• It is widely used in lighting, displays, electronic indicators, and screens.

Additional information:

• Energy efficiency: Up to 90% more efficient than traditional bulbs
  First discovery: H. J. Round – 1907
  Early research: Oleg Losev – 1927
  Practical LED development: James R. Biard – 1961
  First commercial production: October 1962 (Nick Holonyak)

Last verified on 12-03-2026

Explanation

• An optical instrument used to measure the properties of visible light is called a Spectroscope.
• It analyzes the composition and properties of materials based on the light they emit or absorb.
• It helping us understand the physical and chemical properties of objects in the universe.

Last verified on 12-03-2026

Explanation

• Our Solar System is located in the Orion Arm of the Milky Way galaxy.
• It including the Sun and eight planets.
• It consists of about 100–400 billion stars along with large amounts of gas and cosmic dust.

Additional information:

• The Milky Way is a spiral galaxy with a diameter of about 100,000 light-years.
• The nearest large galaxy to the Milky Way is Andromeda, located about 2.5 million light-years away.

Last verified on 11-03-2026

Explanation

• The telescope was first used for astronomical observations in the early 17th century.
• Galileo Galilei first used an improved telescope in 1609 to observe planets like Jupiter, Saturn, and Venus.
• He discovered four large moons of Jupiter (Io, Europa, Ganymede, and Callisto).

Last verified on 11-03-2026

Explanation

• The retina is the light-sensitive layer located at the back of the human eye.
• It contains special cells called rods and cones that detect light and color.
• These cells convert light into electrical signals.
• The signals are then sent to the brain through the optic nerve to produce vision.

Last verified on 11-03-2026

Explanation

• A convex lens is a transparent optical lens that is thicker in the middle and thinner at the edges.
• It bends parallel rays of light towards a single point called the focus.
• Because it brings light rays together, it is called a converging lens.

Additional information:

• Concave lens is also called a diverging lens.

Last verified on 11-03-2026

Explanation

• The molecular structure (double-helix model) of DNA was proposed in 1953.
• This model explained how DNA replicates and carries genetic information in living organisms.
• The discovery was made by James Watson and Francis Crick, two molecular biologists.

Last verified on 11-03-2026

Explanation

• Gene Definition: Basic physical and functional unit of heredity
• Location: Found on chromosomes within DNA
• Function: Codes for proteins or RNA molecules that determine traits
• Types: Structural genes (proteins), regulatory genes (control expression)
• Inheritance: Passed from parents to offspring during reproduction

Last verified on 05-02-2026

Explanation

• A chemical reaction that releases heat energy to the surroundings is called an Exothermic Reaction.
• In such reactions, energy is produced in the form of heat, light, or flames.
• Examples include combustion of fuel, respiration, and neutralization reactions.

Additional information:

• An endothermic reaction, which absorbs heat from the surroundings.

Last verified on 11-03-2026

Explanation

• The branch of chemistry that studies heat energy released or absorbed during chemical reactions is called Thermochemistry.
• It explains how heat changes occur during reactions such as combustion, neutralization, and dissolution.
• It deals with concepts like enthalpy change (ΔH), exothermic reactions, and endothermic reactions.

Last verified on 11-03-2026