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 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

• Aggressive means جارحانہ
• Quarrelsome means جھگڑا
• Violent means متشدد

Last verified on 10-06-2026

Explanation

• The chemical formula for water is H₂O.

Atomic masses:

• Hydrogen (H) = 1 amu each → 2 × 1 = 2 amu
• Oxygen (O) = 16 amu

Total molecular mass = 2 (from H) + 16 (from O) = 18 amu.

Last verified on 07-06-2026

Explanation

• Natural gas contains about 80% to 95% methane.
• It is a hydrocarbon fuel.
• It is the chief (major) component of natural gas.
• It is also a greenhouse gas.
• Chemical formula: CH₄
• It is a clean-burning fuel used in daily life.

Last verified on 07-05-2026

Explanation

• Pressure can be defined as the force acting per unit area.
• The unit of pressure is N/m² (Newton per square meter).
• It is also called Pascal (Pa).
• In SI base units kg⋅m−1⋅s−2
• Derivations from other quantities: p = F / A
• Dimension unit: M L^−1 T^-2.

Additional information 

The SI unit of energy/work is the joule (J)

Last updated on 09-03-2026

Explanation

• The product of mass and velocity is known as momentum. P = MV
• If m is an object's mass and v is its velocity (also a vector quantity), then the object's momentum p is: p=mv
• It is a vector quantity.
• It having both magnitude and direction.
• Common symbols: p, p
• SI unit: kg⋅m⋅s−1
• Dimension MLT^−1

Last updated on 09-03-2026

Explanation

• Carbon has a valency of 4, meaning it can form 4 covalent bonds with other atoms.
• This property allows carbon to form complex organic compounds.
• It is the backbone of all organic molecules.

Additional information:

Examples of Carbon Compounds (5):

1. Methane (CH₄)
2. Ethane (C₂H₆)
3. Glucose (C₆H₁₂O₆)
4. Ethanol (C₂H₅OH)
5. Carbon dioxide (CO₂)

Last verified on 19-01-2026

Explanation

James Chadwick is known for his discovery of the neutron in 1932. 

Proton: Protons were discovered by Ernest Rutherford, before neutrons.

Electron: Electrons were discovered by J.J. Thomson, much earlier than protons or neutrons.

Positron: A positron is the antiparticle of an electron, and it was discovered by Carl Anderson in 1932. 

Explanation

• A, D, E, and K are fat-soluble vitamins.
• Fat-soluble vitamins are absorbed by the body along with dietary fats.
• They are present in foods that contain fats.
• The body stores these vitamins in the liver and fat tissue when they are not in use. 
• Megadoses of fat-soluble vitamins can be toxic.