Explanation

The renewable energy sources are:

• Water energy
• Wind energy
• Tidal energy
• Solar energy
• Hydroelectric
• Ocean energy
• Geothermal energy
• Biomass
• Biogas

The non-renewable energy sources are:

• Fossil fuels or Hydrocarbon fuel (Oil, Natural gas, Coal)
• Nuclear energy

Last verified on 16-03-2026

Explanation

• Gear is a wheel with teeth along its edge that interlock with another gear to transmit motion and force.
• Gears are used to increase or decrease speed, change direction, or increase torque in machines.
• Common in clocks, bicycles, vehicles, and industrial machines.

Last verified on 16-03-2026

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

• A solid has both a definite shape and a definite volume.
• The particles in solids are tightly packed and only vibrate in fixed positions.
• Examples include iron, wood, stone, and ice.

Additional information:

• A liquid has a definite volume but no definite shape.
• A gas has neither definite shape nor definite volume.

Explanation

• Translocation is the process by which food made in the leaves moves to other parts of the plant through the phloem.
• In plants, food is produced in the leaves through photosynthesis.
• This prepared food must be transported to other parts like roots, stems, and fruits.

Last verified on 16-03-2026

Explanation

• A solar day is the time taken by the Earth to complete one full rotation on its axis relative to the Sun.
• Length of a solar day = 24 hours = 1,440 minutes
• Length of a sidereal day = 23 hours 56 minutes 4 seconds
• Earth rotates approximately 360° relative to the Sun in a solar day
• Lunar day = ~24 hours 50 minutes (Moon’s rotation relative to Sun)

Last verified on 15-03-2026

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

• Sound waves first enter the ear through the Ear Canal.
• It is also known as the external auditory meatus.
• From there, they travel to the eardrum, then to the cochlea, and finally to the auditory nerve.

Last verified on 15-03-2026

Explanation

• Transmission is the process where light passes through a material without being absorbed or reflected.
• The light may pass completely unchanged if the material is transparent.

Additional information:

• Reflection – Light bounces back from a surface
• Absorption – Light is taken in by a material and converted to heat
• Refraction – Light bends while passing from one medium to another (like air to water)

Last verified on 15-03-2026

Explanation

Gears can:

• Change speed: Gears can increase or decrease
• Change direction: Gears can change the direction of rotation
• Change force: Gears can increase or decrease the force

However, gears cannot change the fulcrum, which is the pivot point or axis of rotation.

Last verified on 15-03-2026