for every square metres of grass that it eats,a cow gets 3000KJ of energy .it uses 100KJ for growth.1000KJ are lost as heat and 1900KJ are lost in faeces. what percentage of the energy in one square metre of grass is used for growth
Answers
Answer:
Ram and Shyam purchased two electric tea kettles A and B of
the same size, same thickness and the same volume of 0.4 litres. They studied the
specification of kettles as under
Kettle A :
Specific heat capacity =1680J/kgK
Mass =200g
Cost =Rs.400
Kettle B:
Specific heat capacity =2450J/kgK
Mass =400g
Cost =Rs.400
When kettle A is switched on with constant potential source,
the tea begins to boil in 6 min. When kettle B is switched on with the same
source separately, then tea begins to boil in 8 min. The efficiency of
kettle is defined as
Total energy supplied
Energy used for liquid heating
They made discussion on specification and efficiency of kettles and subsequently
prepared a list of questions to draw the conclusions. Some of them are as under
(Assume specific heat of tea liquid as 4200J/kgK and density 1000kg/m
2
.)
The efficiency of kettle B is η=
M
t
S
t
ΔT+M
B
S
A
ΔT
M
t
S
t
ΔT
η=
1680+980
1680
=
2660
1680
×100=62.5%