Energy

Question 1

What is internal energy

Answer 1

the total kinetic and potential energy of all the particles in a system

Question 2

if the temperature in an energy store increases, what does the increase depend on

Answer 2

• the mass of the substance heated
• what the substance is
• the energy input

Question 3

What is specific heat capacity

Answer 3

the amount of energy required to raise the temperature of one kilogram of he substance by one degree

Question 4

What happens to the energy when a lift raises the lift carriage

Answer 4

• it transfers electrical energy to gravitational energy
• some energy is dissipated into the surroundings as heat and sound
• this wasted energy is no longer available for useful transfer

Question 5

how can wasteful energy caused by unwanted transfer be reduced

Answer 5

• lubrication reduces friction that produces heat
• tightening any loose parts prevents any unwanted vibrations wasted as sound energy
• thermal insulation

Question 6

what does the rate of cooling in a building depend on

Answer 6

the thickness and thermal conductivity of the walls

Question 7

name 3 renewable sources of energy

Answer 7

solar, wind, biofuel, geothermal, hydro-electric

Question 8

name 3 non-renewable sources of energy

Answer 8

nuclear fuel, coal, oil, gas