Explanation

• The Mole (mol) is the SI unit of amount of substance, representing 6.022 x 10^23 particles.
• It is used to measure the amount of a substance in a sample.

Explanation

Louis Pasteur (1822–1895) was a pioneering microbiologist and chemist whose work bridged both fields:

As a Chemist:

• Discovered molecular chirality (optical isomers).
• Studied fermentation, proving it was caused by microorganisms.

As a Microbiologist:

• Developed pasteurization (heat treatment to kill microbes in food).
• Created vaccines for rabies and anthrax.
• Disproved spontaneous generation (germ theory of disease).

Explanation

The chemical formula CH₃COOH represents acetic acid, a weak organic acid commonly found in vinegar.

Key Information:

Common Name: Acetic acid (systematic name: ethanoic acid).

Properties:

• Weak acid (partially dissociates in water).
• Pungent smell, sour taste (vinegar contains ~4–8% acetic acid).

Explanation

Xylem and Phloem are specialized conducting tissues in vascular plants:

Xylem: Transports water and minerals from roots to other parts (unidirectional).

Phloem: Transports sugars (photosynthates) from leaves to other parts (bidirectional).

Explanation

The atomic weight of Mercury (Hg) is 200.59 unified atomic mass units (u), as listed on the periodic table.

Key Information:

• Symbol: Hg (from Latin Hydrargyrum)
• Atomic Number: 80
• Standard Atomic Weight: 200.592 u (often rounded to 200.59 u).

Explanation

Longitudinal Wave (Primary Nature):

Sound propagates as compressions and rarefactions (particles vibrate parallel to wave direction).

Example: Sound waves in air.

Mechanical Wave (Medium Dependency):

Requires a medium (solid, liquid, gas) to travel—cannot propagate in a vacuum.

Transverse Wave (In Specific Cases):

In solids, sound can also exhibit transverse wave components (particles vibrate perpendicular to the wave direction).

Explanation

Biology is classified as a natural science.

Because it studies living organisms and life processes through observation and experimentation.

Key Points:

Natural Sciences include:

1. Biology (study of life)
2. Physics (matter/energy)
3. Chemistry (substances/reactions)

Explanation

In the Quran and Bible, it is mentioned that the nation of Hazrat Musa (Moses, A.S.) fasted for 40 days as an act of repentance and devotion to Allah (God).

Key References:

Quran (Surah Al-Baqarah 2:51, 7:142) – Mentions Musa (A.S.) fasting for 40 days on Mount Sinai while receiving the Torah.

Bible (Exodus 34:28) – Confirms Moses fasted 40 days and nights without food or water.

Explanation

The name "Ahmed" was suggested by Hazrat Amina (R.A) while the name "Muhammad" was suggested by Hazrat Abdul Mutalib.

Explanation

In the Fajr (pre-dawn) prayer, there is a significant gap between the Azaan (call to prayer) and the actual Namaz (prayer). This is because:

• Azaan is called early to announce the start of the prayer time.
• Namaz is delayed slightly to allow worshippers to wake up, perform ablution (Wudu), and prepare.