01.
|
i |
Ii |
iii |
iv |
v |
|
A |
D |
B |
C |
A |
02.
i.
Energy value is the amount of energy produced per unit
mass of the fuel.
ii.
Ignition point is the temperature to which the fuel must
be heated before it starts burning.
iii.
Kinetic energy is the energy possessed by the body due to
its motion.
iv.
Potential energy is the energy possessed by the body due to
its position.
03. Major
components of coal are:
Ø
Moisture
Ø
Volatile
matter
Ø
Ash
Ø
Fixed
carbon (Coke)
04. Important
types of coal are:
Ø
Peat
Ø
Lignite
Ø
Bituminous
(soft coal)
Ø
Anthracite
(hard coal)
05. (i) Energy is the ability or capacity of a
body to do work.
(ii) The principle of conservation of energy states that “Energy can neither be created nor destroyed
but it can be transformed from one form to another.”
06.
(i)
Dynamo
(ii)
Electric
cooker, electric iron, heaters, electric bulb
(iii)
Electrical
motor
(iv)
Electric
bell
(v)
Solar
panel, photocells
07. (a) Energy value of a fuel is the amount of
energy produced per unit mass of a fuel.
(b) Data given:
Mass of a petrol (m) = 20 g
Volume of water heated (v) = 2.5 litres
Heat value of petrol (H) = 43 640 KJ/Kg
Required:
Temperature change (∆Q) =?
From:
Energy value =
Energy value =
But, from
Mass of water = density x volume
Mass of water = 1000 kg/m3 x 2.5
litre
Mass of water = (1000 x 2.5/1000) kg
= 2.5 kg
Note: 1 m3 = 1000 dm3/litres
Mass of fuel = (20/1000)
kg è 0.02 kg
Since, 1kg =
1000 g
Then,
43 640 KJ/kg =
= 83.49 K
Ø The
temperature change is 83.49 K
08. (a)
Renewable sources of energy are the sources of energy which are continuously
replaced within a short period of time.
(b) Two main advantages
of biofuels
·
They are
carbon neutral thus they contribute very little to global warming unlike fossil
fuels.
·
Their
supply is almost limitless since biofuels are produced from various sources
such as straw, timber, manure, rice
husks, sugar cane, flaxseed and palm oil.
