Explanation

• A series of steps is called a staircase, stairway, or a flight of stairs

Additional information:

• Tread: The flat, horizontal top surface where you place your foot.
• Riser: The vertical part that forms the gap between one step and the next.
• Nosing: The front, rounded edge of the tread that sticks out over the riser

Last updated 14 August 2026 by NA

Explanation

• Ozone (O₃) is mainly found in the Stratosphere, called the ozone layer.
• It absorbs harmful ultraviolet (UV) radiation from the sun, protecting life on Earth.
• Located roughly 15–35 km above the Earth’s surface.

Last verified on 17-01-2026

Explanation

• A rainbow is produced due to the dispersion of sunlight by water droplets in the atmosphere.
• White sunlight splits into seven colours when it passes through raindrops.
• The formation of a rainbow involves refraction, dispersion, and internal reflection.
• Dispersion is the phenomenon responsible for separating white light into its constituent colours.
• Rainbows are usually seen opposite the Sun after rainfall.

Last verified on 26-07-2026

Explanation

• Nitrogen (N₂): 78%

Additional information:

• Oxygen (O₂): 21%
• Argon (Ar): 0.93%
• Carbon dioxide (CO₂): ~0.04%
• Other gases: ~0.03%

Last verified on 16-05-2026

Explanation

• Sound cannot travel through a vacuum because there are no particles to carry sound vibrations.
• Sound needs a medium such as a solid, liquid, or gas to travel.
• Since space is nearly a vacuum, sound cannot be heard there.
• The speed of sound in a vacuum is 0 m/s.

Additional information:

• Infrasound: Below 20 Hz
• Audible sound: 20 Hz – 20,000 Hz (20 kHz)
• Ultrasound: Above 20 kHz
• Speed of sound in air: 343 m/s
• Speed of sound in water: 1,481 m/s

Last verified on 07-06-2026