Explanation

• A black hole is a region of space where matter has collapsed in on itself.
• It creating an incredibly dense and gravitational field so strong that not even light can escape.
• Black holes are detected via gravitational effects on nearby stars or X-ray emissions.
• Famous example: Sagittarius A* at the center of the Milky Way.

Last verified on 19-03-2026

Explanation

• Sirius means صبح کا ستارہ
• Sirius, also called the Dog Star.
• It is the brightest star in the night sky visible without a telescope.
• It is located in the constellation Canis Major.
• It is about 8.6 light-years from Earth.

Last verified on 19-03-2026

Explanation

• Earth is located in the Milky Way Galaxy.
• It a spiral galaxy containing hundreds of billions of stars.
• Our Solar System is one of the many systems within this galaxy.

Last verified on 19-03-2026

Explanation

• Copper is an excellent conductor of heat.
• It having a high thermal conductivity (386 W/mK).
• This means it can efficiently transfer heat energy with minimal resistance.
• Metals (e.g., iron, copper, silver, mercury, aluminum) are good conductors of heat.

Last verified on 19-03-2026

Explanation

• In liquids and gases, heat is mainly transferred by convection.
• Convection involves the movement of particles carrying heat from one place to another.
• Essential for weather patterns, ocean currents, and heating systems.

Last verified on 19-03-2026

Explanation

• Noise intensity is measured in decibels (dB).
• It indicates the loudness of sound.
• It helps assess noise pollution in cities, industries, and traffic areas.
• Noise pollution affects hearing, stress levels, and sleep.
• Reducing exposure above 85 dB is important for health protection.

Last verified on 19-03-2026

Explanation

• The flash of light from lightning is a form of electromagnetic radiation, and as such, it travels at the speed of light.
• It is denoted by the letter c.

It is equal to:

• 3 x 10^8 meters per second (m/s) in scientific notation.
• 300,000 kilometers per second (km/s) in metric units.
• 186,282 miles per second (mi/s) in imperial units

Last verified on 19-03-2026

Explanation

• Tritium, also known as superheavy hydrogen.
• It has 1 proton and 2 neutrons in its atomic nucleus.

Additional information:

• Protium (¹H) → 1 proton, 0 neutrons
• Deuterium (²H) → 1 proton, 1 neutron

Last verified on 19-03-2026

Explanation

The K orbit, also known as the first electron shell.

• It can hold a maximum of 2 electrons.

The L orbit, also known as the second electron shell.

• It can hold a maximum of 8 electrons.

The M orbit, also known as the third electron shell.

• It can hold a maximum of 18 electrons.

Last verified on 19-03-2026

Explanation

• The mass number (A) is the sum of protons and neutrons present in the nucleus of an atom.
• It is a measure of the total number of nucleons (protons and neutrons) in the nucleus.
• It helps determine the atomic mass and distinguishes isotopes of an element.

Last verified on 19-03-2026