Explanation

Uranium-235 (U²³⁵) is a fissile isotope, meaning it readily undergoes nuclear fission when struck by a neutron.

It is commonly used in nuclear reactors and atomic bombs for this reason.

Explanation

Surface Tension:

"The property of the surface of a liquid that allows it to resist an external force,

due to the cohesive nature of its molecules."

Explanation

The density of air varies with height.

It is maximum near the surface of the earth and decreases as the height increases.

When we climb up a mountain,

the density of air decreases,

and thus the atmospheric pressure also decreases.

Explanation

• The scientist who first discovered that the earth revolves around the sun was Copernicus.
• Earth's Rotational Theory:
  • Rotation can be defined as the spin of Earth on its own axis from west to east direction.
  • It must also be noted that the speed of rotation of the earth is not constant throughout latitudes.
    
  • It differs at different latitudes.

Explanation

Burning magnesium reacts with N₂ to form magnesium nitride (Mg₃N₂).

It also burns in CO₂, breaking it down to MgO and C.

Explanation

Rice is rich in carbohydrates and provides about 360 calories per 100 grams.

It is a major energy source in diets around the world due to its high carbohydrate content.

Explanation

A lead-acid battery consists of a negative electrode made of spongy or porous lead.

The lead is porous to facilitate the formation and dissolution of lead.

Explanation

The material used for bleaching paper pulp is sodium hypochlorite.

It acts as an effective bleaching agent.

It helping to remove color and impurities from the pulp.

Explanation

Colour of the plants is green due to the presence of Chlorophyll۔

Chlorophyll absorbs certain wavelengths of light within the visible light spectrum.

Chlorophyll is the green color pigment which absorbs wavelength from sunlight.

Since the synthesis of food occurs in the presence of sunlight, it is called photosynthesis. 

Explanation

• Chemical digestion of proteins begins in the stomach
• Mechanical digestion (chewing) starts in the mouth,
• The chemical breakdown requires gastric juices, specifically hydrochloric acid (HCL)
• The enzyme pepsin activates and breaks down protein molecules.

Last updated by NS on 20-April-2026