Explanation

• Main Cause: Freon / CFCs
• Effect: Breaks down O₃ molecules → more UV-B radiation
• Other Contributors: Halons, carbon tetrachloride
• Result: Skin cancer, cataracts, climate impact

• The Montreal Protocol (1987) aimed to reduce CFC emissions
• Ozone layer protects Earth from harmful ultraviolet rays

Explanation

• Evaporation is a surface phenomenon that can occur at any temperature.
• It occurs when high-energy molecules escape from the liquid surface into the air.
• Unlike boiling, evaporation does not require the liquid to reach its boiling point.

Last verified on 14-11-2026

Explanation

• A barometer measures atmospheric (air) pressure.
• It helps in weather forecasting, detecting storms, and studying climate changes.
• Two common types of barometers: mercury barometer and aneroid barometer.

Last verified on 13-03-2026

Explanation

• Thermodynamics studies the relationship between heat, temperature, energy, and work.

Additional information:

• First law: Energy cannot be created or destroyed (Law of energy conservation)
• Second law: Heat flows from hot to cold spontaneously
• Third law: Absolute zero cannot be reached
• Zeroth law: Establishes temperature measurement
• Applications: Engines, refrigerators, heat pumps, and power plants

Last verified on 13-03-2026

Explanation

• Amino acids are the building blocks of proteins.
• Proteins are formed when amino acids join together by peptide bonds.
• Proteins are essential for growth, repair, and body functions.
• There are 20 standard amino acids used to make proteins.

Verified & Updated

Explanation

• Carbohydrates are the fastest and main source of energy.
• They are quickly converted into glucose in the body.
• Glucose is used immediately for energy production.
• They provide instant fuel for brain and muscles.

Last verified on 14-05-2026

Explanation

• The general formula for alkanes is CnH2n+2, where n is the number of carbon atoms in the molecule.
• This formula represents the saturated hydrocarbons, also known as paraffins.

Additional information:

• CnH2n is the general formula for alkenes.
• CnH2n+1 is the general formula for alcohols.

Last verified on 13-11-2026

Explanation

• The loss of electrons and protons (H+ ions) is called oxidation.

Additional information:

• Reduction is the gain of electrons.
• Both processes occur together in redox reactions.

Explanation

• A solid is a state of matter that has a fixed shape and a fixed volume.
• Solids maintain their shape and volume unless an external force is applied to change them.

Additional information:

• Liquid: A liquid has a fixed volume but takes the shape of its container.
• Gas: A gas has neither a fixed shape nor a fixed volume.
• It expands to fill its container.

Last verified on 13-11-2026

Explanation

Definition: Possess both magnitude and direction.

Representation: Represented by arrows, where the length indicates magnitude and the arrowhead indicates direction.

Examples: 

• Displacement
• Velocity
• Acceleration
• Force
• Momentum

Additional information 

Difference from Scalars: Unlike scalars, which only have magnitude (e.g., speed), vectors require both to be fully defined

Last updated on 09-03-2026