Explanation

• Bases are substances that have a soapy or slippery feel when touched.
• This property occurs because bases react with oils on the skin, giving a soap-like texture.
• Many bases also turn red litmus paper blue in chemical tests.
• Common bases are used in cleaning agents, soaps, and detergents.

Last verified on 16-03-2026

Explanation

• The iris is the colored part of the eye that controls the size of the pupil.
• By adjusting the pupil size, it regulates the amount of light entering the eye, just like a camera diaphragm.
• Pupil dilation occurs in low light, letting in more light.
• Pupil contraction occurs in bright light, protecting the retina from damage.

Last verified on 15-03-2026

Explanation

• According to the Kinetic Molecular Theory, faster gas particles hit container walls more often.
• More frequent and stronger collisions increase the pressure.
• Higher temperature → higher particle speed → higher pressure.
• Pressure depends on number of collisions of gas molecules with container walls.
• Unit of gas pressure: Pascal (Pa).

Last verified on 13-03-2026

Explanation

• Respiration (breathing) is mainly controlled automatically by the brain’s respiratory center in the medulla oblongata.
• Normally, breathing occurs without conscious control, so it is an involuntary process.
• When a person cannot control breathing voluntarily (e.g., during sleep or unconsciousness), the body automatically continues respiration.

Last verified on 13-03-2026

Explanation

• 1 kilogram (Kg) = 1000 grams (g)
• So, 0.2 Kg = 0.2 × 1000 g = 200 g
• Mass is a measure of matter in an object.

Last verified on 13-03-2026

Explanation

• Acceleration is not a base quantity.

The base quantities are:

• Length (L)
• Mass (M)
• Time (T)

Last verified on 13-03-2026

Explanation

• The ozone layer is a part of the Earth’s stratosphere that absorbs most of the Sun’s harmful ultraviolet (UV) radiation.
• Without it, UV rays could cause skin cancer, cataracts, and environmental damage.
• It is found approximately 15–35 km above Earth’s surface.

Last verified on 13-03-2026

Explanation

• Remote Sensing is the science of collecting information about the Earth’s surface without direct contact.
• It is mainly done using satellites equipped with special sensors and cameras in space.
• These satellites capture images and data used for mapping, weather forecasting, and environmental monitoring.

Last verified on 12-03-2026

Explanation

• Wind energy is a form of kinetic energy produced by the movement of air.
• This moving air rotates the blades of wind turbines or fans to generate electricity.
• Wind power is an important renewable and clean energy source.

Last verified on 12-03-2026

Explanation

• Meteorologists are scientists who study the atmosphere and weather conditions.
• They forecast tornadoes, hurricanes, floods, and other weather events using satellites, radar, and computer models.
• Their work helps in early warning systems and disaster management.

Last verified on 12-03-2026