Explanation

• Mangrove forests act as barriers against cyclones.
• Mangroves reduce erosion by trapping sediments, stabilizing the coastal zone and thus protecting the coast from storm surges and cyclones.
• Mangroves in Pakistan are found along the coastline of Sindh and Balochistan.

Last verified on 06-06-2026

Explanation

• Over-damping occurs when damping force is very large.
• The system returns to equilibrium without oscillating.
• Because of strong resistance, motion becomes very slow.
• It takes more time compared to critical damping.

Last verified on 05-06-2026

Explanation

• Physical pendulum depends on moment of inertia (I) and distance (d) from pivot to center of mass.
• Time period increases when mass is farther from pivot (larger d).
• Standard formula is T = 2π√(I/Mgd).

Last verified on 05-06-2026

Explanation

• Zener diode is mainly used as a constant voltage regulator.
• It operates in the reverse breakdown region.
• In this region, voltage remains almost constant even if current changes.

Last verified on 05-06-2026

Explanation

• The average distance covered by an alpha particle in air before losing its ionizing power is called its range.
• Alpha particles lose energy continuously while moving through air.
• They stop ionizing after traveling a certain distance.
• This stopping distance is not straight-line path always due to collisions.

Last verified on 05-06-2026

Explanation

• Lyman series lies in the ultraviolet (UV) region of hydrogen spectrum.
• It is produced when an electron falls to the first energy level (n = 1).
• These transitions release high-energy photons.

Additional information:

• Balmer series lies in the visible region.
• Paschen and Brackett are in infrared.

Last verified on 05-06-2026

Explanation

• Oxidation of secondary alcohols produces ketones.
• Secondary alcohols have –OH group attached to a carbon bonded with two other carbons.
• During oxidation, hydrogen is removed and a carbonyl (C=O) group is formed.

Additional information:

• Primary alcohol → Aldehyde → Acid
• Secondary alcohol → Ketone (stops here)
• Tertiary alcohol → No easy oxidation

Last verified on 05-06-2026

Explanation

• Natural rubber consists of polymers of isoprene (C₅H₈).
• Isoprene is a five-carbon unsaturated hydrocarbon.
• Natural rubber is chemically known as cis-1,4-polyisoprene.
• It is obtained from the latex of rubber plants.

Last verified on 05-06-2026

Explanation

• Chromatography mainly works on the principle of adsorption.
• Different substances are adsorbed to different extents on a stationary phase.
• This causes separation of components in a mixture.

Last verified on 05-06-2026

Explanation

• Trichinosis is a disease caused by a parasitic worm.
• It is caused by Trichinella spiralis.
• It spreads through undercooked or infected meat.
• It affects muscles and digestive system in humans.

Last verified on 04-06-2026