Explanation

• Microearthquakes are earthquakes with a magnitude of less than 2.0.

Additional information:

• Minor earthquakes: Commonly refers to low-magnitude earthquakes; exact ranges vary by classification.
• Major earthquakes: Generally refers to earthquakes of magnitude 7.0 or higher.

Last verified on 09-10-2026

Explanation

• Comets are small celestial bodies mainly composed of ice, dust, and rocky material.
• They travel around the Sun in highly elliptical or elongated orbits.
• Halley’s Comet, which returns approximately every 76 years.

Additional information:

• Asteroids: Mainly rocky or metallic bodies.
• Meteoroids: Small pieces of rock or metal moving through space.

Last verified on 05-10-2026

Explanation

• Rear view mirrors in vehicles are convex mirrors.
• They give a wider field of view.
• Images formed are virtual, upright, and smaller.
• This helps drivers see more traffic behind them.
• It is a curved mirror that bulges outward.
• It is commonly used in side mirrors of cars, buses, and motorcycles.

Last verified 26-04-2026

Explanation

• Ole Rømer was the first person to experimentally demonstrate that light has a finite speed in 1676.
• He used observations of Jupiter’s moon Io to estimate the speed of light.

Additional information:

• The modern accepted speed of light in vacuum is 299,792,458 m/s.

Last verified on 07-10-2026

Explanation

• Jupiter has the fastest rotation of all planets.
• It completing one rotation in about 9 hours 56 minutes.

Additional information:

• Venus has the slowest rotation.
• It taking about 243 Earth days.
• Earth: ~24 hours
• Mars: ~24 hours 37 minutes.

Last verified on 06-10-2026

Explanation

• The correct mathematical form is V = IR.
• Here V = voltage, I = current, R = resistance.
• Ohm’s law states that current is directly proportional to voltage when temperature is constant.
• It describes the relationship between voltage, current, and resistance.

Last verified on 12-04-2026

Explanation

• Mercury is closest to the sun.
• It is mostly made up of iron.
• It's surface covered with craters.
• It has no atmosphere and no moons.
• It's smallest planet.

Last verified on 06-10-2026

Explanation

• 1 Megawatt (MW) = 1,000,000 watts (W) = 10⁶ W.
• The watt (W) is the SI unit of power.

Additional information:

• 1 kilowatt (kW) = 10³ W
• 1 gigawatt (GW) = 10⁹ W
• 1 watt (W) = 1 W
• 1 milliwatt (mW) = 10⁻³ W

Last verified on 06-10-2026

Explanation

• Wavelength is the distance between two successive corresponding points of a wave, such as two crests.
• It can be measured in meters (m), centimeters (cm), and nanometers (nm).
• The SI unit of wavelength is meter (m).
• Nanometer (nm) is commonly used for very short wavelengths, especially in light.

Conversions:

• 1 m = 100 cm
• 1 cm = 10⁻² m
• 1 nm = 10⁻⁹ m

Last verified on 06-10-2026

Explanation

• The SI unit of power is the watt (W). 
• A watt is equal to one joule of work done per second. 
• Symbol: W
• Definition: 1 watt = 1 joule per second
• Named after: James Watt

Last verified on 05-10-2026