Explanation

• The SI unit of electric current is Ampere (A).
• Electric current measures the flow of electric charge.
• Defined using the elementary charge (e = 1.602176634 × 10⁻¹⁹ C).
• Named after: André-Marie Ampère (scientist).
• 1 Ampere = 1 Coulomb per second (1 A = 1 C/s).

Last verified on 08-06-2026

Explanation

• Light Year is the distance that light can travel in one year.
• The distance light travels in one year is known as light year.
• 1 light year is equal to 9.5 x 10¹²km.

Last verified on 30-03-2026

Explanation

• Sound waves in solvents (like liquids) travel as longitudinal waves, where particles vibrate parallel to the direction of wave propagation.
• These are a type of mechanical wave, requiring a medium to travel.

Last verified on 19-03-2026

Explanation

• The audible range of a normal human ear is 20 Hz to 20,000 Hz (20 kHz).
• Sounds below this range are called infrasound,
• Sounds above it are called ultrasound. 
• Lower limit: 20 Hz (deep rumbles)
• Upper limit: 20,000 Hz (high-pitched squeaks)

Additional information

• Adult change: The upper limit often drops to 15,000–17,000 Hz as people get older. 
• Unit of frequency: Hertz (Hz)

Last updated 27-07-2026 by NA

Explanation

• The SI unit of electrical resistance is Ohm (Ω).
• It measures how much a material opposes the flow of electric current.
• Higher resistance means less current flows.
• It is defined by V = IR (Ohm’s Law).
• 1 Ohm = 1 Volt per Ampere.

Last verified on 10-06-2026

Explanation

When white light passes through a prism, it splits into 7 colors, forming a spectrum known as a rainbow:

1. Red
2. Orange
3. Yellow
4. Green
5. Blue
6. Indigo
7. Violet

The separation of visible light into its different colours is known as dispersion.

Last verified on 08-06-2026

Explanation

• Atoms are made of subatomic particles: protons, neutrons, and electrons.
• Mass number represents the total number of heavy particles in nucleus.
• Only protons and neutrons contribute to atomic mass.

Last verified on 14-05-2026

Explanation

• Almost all the mass of an atom is concentrated in its nucleus.
• The nucleus contains protons and neutrons, which are much heavier than electrons.
• Electrons revolve around the nucleus but contribute very little to atomic mass.
• The nucleus is located at the center of the atom.
• Ernest Rutherford discovered the nucleus through the gold foil experiment in 1911.

Last verified on 09-05-2026

Explanation

• Our Solar System is located in the Orion Arm of the Milky Way galaxy.
• It including the Sun and eight planets.
• It consists of about 100–400 billion stars along with large amounts of gas and cosmic dust.

Additional information:

• The Milky Way is a spiral galaxy with a diameter of about 100,000 light-years.
• The nearest large galaxy to the Milky Way is Andromeda, located about 2.5 million light-years away.

Last verified on 11-03-2026

Explanation

• The Sun is a star at the center of our solar system with a surface temperature of about 6000 °C (Sun’s core is even hotter, ~15 million °C).
• It provides light and heat, essential for life on Earth.
• The Sun’s energy drives weather, photosynthesis, and climate.

Last verified on 18-03-2026