Explanation

The boiling point is the temperature at which a pure liquid changes state from liquid to gas at standard atmospheric pressure.

Key Points:

• The melting point is the temperature at which a solid changes state to a liquid.
• The freezing point is the temperature at which a liquid changes state to a solid.

Explanation

Specific heat capacity is the thermal energy transfer required per unit mass to increase the temperature of a substance by 1°C (or 1 K).

It is a measure of how much heat energy a substance can absorb or release per unit mass per unit temperature change.

Explanation

Heat of vaporization is the amount of heat energy required to convert a substance from its liquid state to its gaseous state, without changing its temperature.

This energy is used to break the intermolecular forces between the molecules, allowing them to escape into the gas phase.

Explanation

Heat capacity is the amount of heat energy required to change the temperature of a substance by a given amount.

It is calculated as the product of the mass of the substance and its specific heat capacity:

Heat Capacity = mass x specific heat capacity

Explanation

Coal, gas, and oil are all examples of fossil fuels, which are energy resources formed from the remains of ancient plants and animals over millions of years.

Fossil fuels are non-renewable sources of energy.

Additional Information:

• Tidal energy is energy generated from ocean tides
• Nuclear energy is energy generated from the nucleus of atoms
• Biomass energy is energy generated from organic matter (plants, wood, waste)

Explanation

Nuclear energy is the energy released from the nucleus of an atom, either through fission (splitting of atoms) or fusion (combination of atoms).

This energy is released in the form of heat and radiation, and is harnessed in nuclear power plants to generate electricity.

Key Points:

• Solar energy is energy from the sun
• Geothermal energy is energy from the Earth's internal heat
• Tidal energy is energy from ocean tides

Explanation

The potential energy (PE) of an object is calculated as:

PE = mass x gravity x height

= 1 kg x 10 m/s^2 x 1 m

= 10 Joule

So, the energy possessed by the body is 10 Joule.

Explanation

The kinetic energy (K.E) of an object is calculated as:

• K.E = (1/2) x mass x velocity^2
• = (1/2) x 1 kg x (1 m/s)^2
• = 0.5 Joule
• = 1/2 Joule

So, the kinetic energy of the body is 1/2 Joule or 0.5 Joule.

Explanation

The work done on an object is calculated as the product of the force applied and the distance over which the force is applied:

Work = Force x Distance

= 6 N x 2 m

= 12 J

So, the work done is 12 Joule.

Explanation

When a gas changes into a liquid, the molecules:

• Move closer together (their distance decreases)
• Lose kinetic energy (they slow down)