Paper 1 Heating And Static Elecricity

Question 1

Double glazing

Answer 1

Reduces conduction

2 layers so further for heat to travel. Air- good insulator (gas)

Question 2

Cavity wall insulation

Answer 2

Reduces conduction and convection
2 layers so further for heat to travel
Air is good insulator
Pockets of air reduce flow of convection

Question 3

Loft insulation

Answer 3

Reduces conduction and convection

Fibre glass had pockets of trapped air

Question 4

Foil behind radiators

Answer 4

Reduces radiation

Good reflector/ poor absorber heat reflected back into room

Question 5

Draught excluders

Answer 5

Reduces convection

Closes gap under door so air can’t flow through

Question 6

Curtains

Answer 6

Reduces convection (+conduction and radiation)
Blocks gap, is thick, its opaque so absorbs radiation but doesn't transmit

Question 7

Carpets

Answer 7

Reduces conduction

Made of thick insulating materials often with air pockets to reduce heat loss

Question 8

Payback time=

Answer 8

Cost of insulation/ annual saving

Question 9

What is static electricity

Answer 9

When charge ‘builds up’ on an object and doesn’t move e.g rubbing a rod

Question 10

What happens when you rub a rod with a cloth

Answer 10

Fiction causes electrons to move from rod to cloth

Friction causes electrons to move from cloth to the rod

Question 11

What happens if there are 2 rods of the same or different material

Answer 11

Different will attract

Same will repel

Question 12

What’s an electric field

Answer 12

Region where a charged object would experience a force

Question 13

How can the electric field be represented using field lines

Answer 13

Direction of f.l is the direction of force that’d act on small positive charge at that point
Spacing of f.l depends on strength of force. Closer together the lines, the stronger the force

Question 14

What are the files lines like when an object is positively charged

Answer 14

The field lines point outwards because like charges repel

Question 15

What are the files lines like when an object is negatively charged

Answer 15

The field lines point inwards because unlike charges attract

Question 16

What happens to the field lines when you move away from charged object

Answer 16

They spread out so the force becomes weaker

Question 17

Van de Graff generators

Answer 17

Charge builds up on dome due to electrons ‘rubbed off’ by belt. If big enough charge build up voltage becomes high enough to ionise air molecules and electrons ‘jump’ down to earth This is an electric current

Question 18

What happens when the small metal dome is moved closer to dome

Answer 18

Electric field becomes stronger. If close enough then force is strong enough to make electrons move in a spark

Question 19

Danger of refuelling a plane

Answer 19

Fuel gains electrons from pipes making pipe positive and fuel negative. Resulting voltage may cause a spark

Question 20

Solution to refuelling a plane

Answer 20

Either earth the fuel tank with copper rod or connect the tanker to the plane by a copper conductor