Explanation

• Solar and wind energy are renewable sources of energy, meaning they are sustainable and will not run out.
• Solar energy is generated from the sun's rays.
• Wind energy is generated from the wind.

Last verified on 09-02-2026

Explanation

• The Moon is Earth’s only natural satellite.
• Diameter – 3,474 km
• Distance from Earth – 384,400 km
• Orbital period – 27.3 days
• Surface gravity – 1/6th of Earth
• First human landing – Apollo 11, 1969

Last verified on 18-03-2026

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

Definition: Possess both magnitude and direction.

Representation: Represented by arrows, where the length indicates magnitude and the arrowhead indicates direction.

Examples: 

• Displacement
• Velocity
• Acceleration
• Force
• Momentum

Additional information 

Difference from Scalars: Unlike scalars, which only have magnitude (e.g., speed), vectors require both to be fully defined

Last updated on 09-03-2026

Explanation

• Weight is a vector quantity
• Because it is a force defined as the product of mass and the acceleration due to gravity (W = mg).
• It has both magnitude (amount of force) and direction (downward, towards the center of the Earth)

Additional information 

Mass,  Time, and temperature are scalar quantities

Last updated on 09-03-2026

Explanation

Scalar quantities are physical quantities that have only magnitude (amount or size) but no direction.

Examples of scalar quantities include:

• Mass
• Temperature
• Time
• Energy
• Distance

Last verified on 07-02-2026

Explanation

The mass of Earth is approximately 6.0 x 10^24 kilograms (5.98 x 10^24 kg).

This is a widely accepted scientific value, based on various measurements and calculations, including:

• Gravity measurements
• Satellite orbits
• Seismological data
• Planetary formation models

Explanation

• The shortest distance between two points is called displacement.
• Displacement is a measure of the straight-line distance between two points.
•  It is a vector quantity.

Key Point: The longest distance between two points is called the circumference (if the points are on a circle) or a diagonal (if the points are on a polygon or a rectangle).

Explanation

Neutral equilibrium is a state where the body is balanced, but the slightest disturbance will not cause it to return to its original position or topple over.

In this state, the center of gravity (CG) remains at the same height, regardless of the slight tilt or displacement.

Key Points: 

• A body is in unstable equilibrium after slight tilt if its center of gravity remains above the point of contact.
  
• A body is in stable equilibrium after slight tilt if its center of gravity remains above the point of contact.
  

Explanation

The melting point of ice at normal atmospheric pressure is 0 °C (zero degrees Celsius).

Key Points:

• 0 K (zero Kelvin) is equivalent to -273.15 °C, which is absolute zero, the lowest possible temperature.
• 100 °C is the boiling point of water at normal atmospheric pressure.