Explanation

• The hottest planet in our solar system is Venus.

Additional information:

• The black planet is called Venus.
• The second-closest planet to the Sun is Venus.
• Slowest Rotating Planet
• No moon
• Similar in size to Earth

Last verified on 30-03-2026

Explanation

• Neptune is the farthest planet.
• It was visited by the spacecraft Voyager 2.
• It's is a very windy place.
• It has six rings.
• It has 14 moons.

Last verified on 24-06-2026

Explanation

• The weight of a body on Earth is the gravitational force acting on it.
• Since the body already weighs 51 N on the surface of Earth, its weight on Earth remains 51 N.
• Formula: Weight = Mass × Gravity (W = mg).

Last verified on 24-06-2026

Explanation

• 1 hp = 746 W
• 1 hp = 0.746 kW
• 1 kW = 1.34 hp
• 1 W = 0.00134 hp
• Standard unit system: SI unit of power is Watt

Last verified on 23-06-2026

Explanation

• The efficiency of a diesel engine is about 30–40%.
• It means only this percentage of fuel energy is converted into useful work.
• The remaining energy is lost as heat, friction, and exhaust gases.
• Diesel engines are generally more efficient than petrol engines.

Last verified on 23-06-2026

Explanation

• Solar plates consist of photovoltaic (PV) cells.
• PV cells convert sunlight directly into electrical energy.
• These cells work on the photovoltaic effect. 
• They are usually made of semiconductor materials like silicon.

Additional information:

• Discovered photovoltaic effect: 1839 by Edmond Becquerel

Common types of solar cells:

1. Monocrystalline silicon cells
2. Polycrystalline silicon cells
3. Thin-film solar cells

Last verified on 23-06-2026

Explanation

• The audible range of a normal human ear is 20 Hz to 20,000 Hz (20 kHz).
• Below 20 Hz: Infrasound
• Above 20 kHz: Ultrasound
• Unit of frequency: Hertz (Hz)

Last verified on 23-06-2026

Explanation

• Mercury is the smallest planet in our solar system.
• Mercury with a diameter of 4,879 km (3031.67 mi).
• Nearest Planet to Sun.
• Fastest Planet.

Last verified on 23-06-2026

Explanation

• Theory proposed by: Charles Darwin
• Book published: 1859
• Book name: On the Origin of Species
• Key concept: Natural Selection
• Voyage that inspired him: HMS Beagle expedition (1831–1836)

Last verified on 21-06-2026

Explanation

• Discoverer: Victor Hess
• Year: 1912
• Method: High-altitude balloon experiments
• Nobel Prize: 1936 (Physics)
• Field: Astrophysics / Space radiation

Last verified on 20-06-2026