Explanation

• Global Positioning System (GPS) is a satellite-based navigation system used to monitor the location and movement of vehicles, ships, and aircraft.
• Developed by the United States, it provides accurate position, navigation, and timing information worldwide.
• Widely used in transportation, mapping, military operations, and smartphones.

Last verified on 12-03-2026

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

• Solar panels convert sunlight into electrical energy using special cells.
• Solar energy is a renewable and clean source of energy.
• These cells are called photovoltaic (PV) cells because they generate electricity when exposed to light.
• The technology is based on the photovoltaic effect, discovered in 1839.

Last verified on 11-03-2026

Explanation

• Bacteria are prokaryotic organisms, meaning they do not have a true nucleus.
• Their genetic material (DNA) is not enclosed in a membrane-bound nucleus.
• Instead, the DNA is present in a region called the nucleoid within the cytoplasm.
• Therefore, bacterial DNA is found floating in the cytoplasm of the cell.

Additional information:

• In contrast, eukaryotic cells (plants, animals, fungi) have DNA enclosed inside a nucleus.

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

• 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

Explanation

• The formation of hydrogen and oxygen from water, which is an example of a decomposition reaction: 2H2O → 2H2 + O2
• In this reaction, water (H2O) decomposes into hydrogen (H2) and oxygen (O2).

Last verified on 11-03-2026

Explanation

• A Telescope is an optical instrument used to observe distant objects such as stars, planets, and galaxies.
• It collects and magnifies light or other forms of electromagnetic radiation.
• The term “telescope” was coined in 1611 by the Greek mathematician Giovanni Demisiani.

Last verified on 10-03-2026

Explanation

• When water cools from 4°C to 0°C, it expands as it freezes into ice.
• Unlike most substances, water’s maximum density is at 4°C; below this temperature, the volume increases and density decreases.
• This is why ice floats on water.

Last verified on 10-03-2026