Solar Cooking Pot

Heat-meaning,concept of specific heat capacity(solar cooking pot)
THE ANSWER:
a)i. Specific heat capacity is amount of heat require to increase the temperature by one degree and by mass 1kg.

ii. Compare the specific heat capacities (SHC) of aluminium and copper and the effects on the increase in temperature

- the SHC of aluminium is higher than copper
- the increase in temp. in copper is faster than aluminium

- the bigger the specific heat capacities, the lower the increase in temperature

b) Immersion heater : power input of 36W, 8 minutes to heat up aluminium block which has a mass of 1.0 kg.
i. Heat energy supplied by the heater : E = VIt
= P x t
= 36 x (8 x 60)
= 17280 J

ii. SHC if temperature rises is 18 degree : c = 17280/1x18
= 960 J/kg c

iii. Value calculated is larger than that reported in theory because heat lost to the surrounding.

c) Modification of a simple cooking pot.

i. M : low specific heat capacity
E : the pot get hot easily
ii. M : holder made of insulating
E : temperature doesn't increase rapidly
iii. M : low density
E : easier to carry
iv. M : use pot that has cover
E : avoid the heat lost to surrounding
v. M : low oxidation
E : not rust easily

a)i. Power rating of 4.5 V, 24 W is the bulb will consume 24 J of electrical energy every 1 second if it is connected to a 4.5 V supply.

ii. Characteristics of materials for making the bulb filament.

i. C : high resistivity
E :
ii. C : high melting point
E : avoid it melt easier
iii. C : low density
E : easier to carry
iv. C : low of oxidation rate
E : not rust easily