Specific Heat Capacity and Efficiency

Question 1

Different materials have….

Answer 1

Different specific heat capacity.

Question 2

Specific heat capacity

Answer 2

Is the amount of energy needed to raise the temperature of 1kg of a substance by 1 degrees.

Question 3

Conservation of energy principle

Answer 3

Energy can be transferred usefully, stored or dissipated, but can never created or destroyed.

Question 4

Dissipated energy

Answer 4

When energy is transferred between stores, not all energy is transferred usefully into the store you want it to go to.

Question 5

Power

Answer 5

Is the rate of energy transfer, or rate of doing work. Measured in watts. 1 watt is 1 J of energy transferred, per seconds.

Question 6

Lubricants

Answer 6

Are liquids or oils, so they can flow easily between objects to coat them. Can be used to reduce the friction between the object’s surfaces when they move.

Question 7

Conduction

Answer 7

When an object is heated, the particles vibrate and collide. During this collision energy is transferred between the particles.

Question 8

Convection

Answer 8

Liquids and gases can flow, the warmer and less dense region will rise above cooler regions. So energetic particles move away from hotter to cooler regions.

Question 9

Insulation

Answer 9

Reduces the rate of energy transfer by heating.

Question 10

Thick walls

Answer 10

Thick walls that are made from material with a low thermal conductivity.

Question 11

Cavity walls

Answer 11

Made up of inner and outer wall with air gap in the middle(reduce conduction). Can be filled with foam(reduce convection)

Question 12

Loft insulator

Answer 12

Reduce convection currents, being created in lofts.

Question 13

Double-glazed windows

Answer 13

They have an air gap between two sheets of glass to prevent energy lose by conduction.

Question 14

Draught excluders

Answer 14

Around doors and windows reduce energy transfer by convection.