Explanation

• Nitrous oxide, commonly known as laughing gas.
• It is a colorless, non-flammable gas used in medicine.
• Nitrous oxide (N₂O) causes temporary laughing and relaxation.

Additional information:

• Nitrous oxide was discovered by Joseph Priestley in 1772.

Last verified on 18-01-2026

Explanation

A myopic defect can be corrected by using a concave lens of suitable power. 

Myopia is a disease related to Eye

Myopia is a common vision condition in which we can see objects near to us clearly, but objects farther away are blurry.

Myopia means دورکی نظر کی کمزوری

Explanation

Studies show that it takes an average of 8 minutes and 20 seconds for sunlight to move from the sun to the earth.

Sunlight moves at the speed of light.

You can see that the distance of the sun from the earth = 149.6 x 106 km.

Photons emitted from the surface of the sun need to traverse the vacuum of the universe to reach our eyes.

Explanation

Radioactivity was discovered by Henri Becquerel in 1896.

They discovered radioactivity proving that the uranium emitted radiation without an external source of energy such as the Sun

Marie Curie with her husband Pierre Curie, coined the term radioactivity.

In 1903, Henry Becquerel shared the Nobel Prize for Physics with Pierre and Marie Curie

Ernest Rutherford did many experiments studying the properties of radioactive decay (alpha, beta, and gamma)

Explanation

Thomas Alva Edison was an American inventor.

He developed many devices: 

• Electric power generation 
•  Mass communication
•  Sound recording
• Motion pictures.

Explanation

The blue whale, a marine mammal in the suborder of baleen whales.

It is the largest known animal to have ever existed.

It measuring up to 30 meters (98 feet) in length and weighing 180 metric tons (200 short tons) or more.

Explanation

The intensity of an earthquake is measured by the Richter scale.

It quantifies the energy released.

It was developed in 1935.

The Richter scale is used in seismology, the study of earthquakes.

Explanation

A fission reaction is a chemical reaction in which an atomic nucleus splits into smaller parts, releasing energy.

It typically occurs in nuclear reactors and atomic bombs.

Explanation

Silicon (Si) is the element most commonly used to fabricate solar cells and transistors.

Silicon is a semiconductor material that is widely used in the production of electronic components, including:

• Solar cells (photovoltaic cells)
• Transistors
• Microprocessors
• Diodes

Explanation