energy transfers

Question 1

energy stores

Answer 1

kinetic

chemical

thermal

gravitational

magnetic

electrostatic

elastic

nuclear

Question 2

principle of conservation of energy

Answer 2

Amount of energy always remains the same
there are various stores of energy
energy can be transferred from one store to another but energy cannot be created or destroyed

Question 3

efficiency

Answer 3

the ratio of the useful energy output to the total energy supplied

Question 4

how can energy be transferred

Answer 4

Mechanically: gravity accelerates an object giving it kinetic energy

Electrically: when current passes through a lamp and it emits light and heat

Heating: fire is used up to heat an object

Radiation: vibrations cause waves to travel through air as sound

Question 5

conduction

Answer 5

Thermal energy in solids and liquids can be transferred by the vibration of particles

non metals are usually poor conductors known as thermal insulators

as a substance is is heated up, molecules vibrate more- hitting and cause adjacent molecules to vibrate more too, transferring heat energy from hotter parts to cooler parts

Question 6

insulators

Answer 6

transfer heat energy much slowly so they are used to reduce unwonted energy transfers such as in homes

Question 7

metals as conductors

Answer 7

Usually good conductors

the electrons can leave the atoms and move freely among positively charged ions

as metal is heated,, ions and electrons vibrate more

free electrons collide with ion and transfer heat energy from hotter parts to cooler parts