Explanation

• The ozone layer acts as Earth’s natural sunscreen, protecting life from the sun’s harmful ultraviolet (UV) radiation.
• UV radiation can cause skin cancer, eye damage, and harm to plants and animals.

Additional information:

• Chemical Formula: O₃ (three oxygen atoms)
• Layer Location: Stratosphere, 15–40 km above Earth
• Function: Absorbs UV-B and UV-C rays from the Sun
• Depletion Causes: Air pollution, CFCs, industrial chemicals
• Protection Measures: Reduce CFC use, ozone-friendly products

Last verified on 09-03-2026

Explanation

Red is the top (outermost) color of the rainbow.

Due to having the longest wavelength of visible light (approx. 620–750 nm)

There are seven colours in a rainbow:

1. Red

2. Orange

3. Yellow

4. Green

5. Blue

6. Indigo

7. Violet

Last updated question 26 feb 2026

Explanation

Greenhouse gases trap heat primarily by absorbing and re-emitting infrared radiation emitted from the Earth's surface

Molecules with three or more atoms, such as CO2 and methane,

Allow them to absorb this longwave radiation and radiate it back towards the surface

Last updated question 25 feb 2026

Explanation

Nitrous Oxide is significantly more potent at trapping heat than methane and carbon dioxide

N2O absorbs infrared radiation very strongly and stays long in the atmosphere.

It has a GWP of approximately 265–298, making it nearly 300 times more potent than CO₂ per unit

Explanation

• Cause: Primarily due to excess greenhouse gases like CO₂, CH₄, and N₂O from human activities.
• Effects: Rising temperatures, melting glaciers, extreme weather, and sea-level rise.

Last verified on 08-02-2026

Explanation

• A wind vane (also called a weather vane) shows the direction from which the wind is blowing.
  • Usually installed on rooftops or meteorological stations.
  • Works with a rotating pointer that aligns with the wind direction.

Last verified on 01-02-2026

Explanation

Oxygen is a vital component of the Earth's atmosphere (making up about 21%) and is essential for life

Therefore, oxygen is not considered a part of smog.

Smog in Pakistan mainly consists of harmful air pollutants.

These include sulphur dioxide, nitrogen oxides, and carbon monoxide.

Explanation

Luminosity is the total amount of energy a star emits per second.

It depends on the star’s size and temperature.

Brightness is how bright the star appears from Earth, which can vary with distance.

Magnitude is a scale to measure stellar brightness.

Explanation

Air always moves from regions of high pressure to low pressure.

This movement creates wind and drives weather patterns.

The greater the pressure difference, the stronger the wind.

High-pressure areas are usually associated with clear skies.

Low-pressure areas often bring clouds and precipitation.

Explanation

The Sun produces energy through nuclear fusion in its core.

In fusion, hydrogen nuclei combine to form helium, releasing huge energy.

This energy radiates as sunlight, heat, and solar radiation.

Fusion is different from fission, which splits heavy nuclei.

Solar energy powers life on Earth and can be harnessed for electricity.