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

• Conduction is the process of heat transfer through direct contact of molecules.
• In solids, especially metals, molecules vibrate and pass energy to neighboring molecules.
• No movement of the substance itself is required; only energy is transferred.

Last verified on 13-03-2026

Explanation

• A thermal conductor is a material that allows heat to pass through it easily.
• Metals like copper, aluminum, and iron are good thermal conductors.
• Thermal conduction occurs mainly in solids where particles are closely packed.
• In contrast, thermal insulators (like wood, plastic, and rubber) resist heat flow.

Last verified on 13-03-2026

Explanation

• Green plants use carbon dioxide (CO₂) from the atmosphere to make food via photosynthesis.
• In photosynthesis, CO₂ + H₂O → Glucose + O₂ (with sunlight and chlorophyll).

Last verified on 13-03-2026

Explanation

• The symbol ⁴₂He indicates helium has 2 protons (atomic number = 2) and mass number = 4.
• In a neutral atom, the number of electrons = protons, so helium has 2 electrons.

Last verified on 13-03-2026

Explanation

• The same atomic number (Z) → same number of protons
• Different mass numbers → different number of neutrons

Explanation

• The freezing point of water is 0°C (32°F), where water changes from liquid to solid.
• The melting point is also 0°C, where ice changes from solid to liquid.
• Freezing and melting are opposite processes occurring at the same temperature.

Last verified on 13-03-2026

Explanation

• Liquids have no fixed shape but have a fixed volume.
• Particles are close together but can slide past each other, allowing the liquid to flow.

Additional information:

• Solid: Are tightly packed and stay in a fixed position
• Gas: Are widely spaced and move freely in any direction

Last verified on 13-03-2026

Explanation

• Glucose is a simple sugar (monosaccharide) and a primary source of energy for cells.
• Its chemical formula is C6H12O6.

Additional information:

• Fructose: C6H12O6 (same formula as glucose, different structure)
• Galactose: C6H12O6
• Ribose: C5H10O5
• Deoxyribose: C5H10O4
• Sucrose (disaccharide): C12H22O11

Last verified on 13-03-2026

Explanation

• The spleen is not part of the digestive tract; it is part of the lymphatic system and helps in blood filtration and immune response.

Additional information:

Main components of human digestive tract:

• Mouth – ingestion and initial digestion
• Oesophagus – food passage
• Stomach – protein digestion
• Small intestine – nutrient absorption
• Large intestine / Colon – water absorption and feces formation

Last verified on 13-03-2026