Explanation

• Sputnik-1 was launched by the USSR (Soviet Union) on 4 October 1957.
• It was the world's first artificial satellite, beginning of the Space Age.
• It started the Space Race between the Soviet Union and the United States.
• Launch Site: Baikonur Cosmodrome, Kazakhstan
• Weight: 83.6 kg
• Orbital Period: About 96 minutes

Last verified on 09-03-2026

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

• Silver reflects approximately 95% of visible light.
• It is one of the best natural reflectors of visible light.
• Because of its high reflectivity.
• Silver is widely used in mirrors and optical instruments.
• It produces bright and clear reflections.

Last verified on 07-06-2026

Explanation

• Interference occurs when two waves overlap or cross each other.
• The waves may produce a stronger wave (constructive interference) or a weaker wave (destructive interference).
• It is a fundamental property of all types of waves, such as light, sound, and water waves.

Last verified on 07-07-2026

Explanation