Answer:
a. Both wires have the same resistivity
Explanation:
For the resistance of a wire , following formula holds good .
R = ρ l / S , R is resistance , l is length , S is cross sectional area and ρ is resistivity of the material that the wire is made of. Resistance is dependent on length and cross sectional area but resistivity does not depend upon length or cross sectional area . It only depends upon the type of material.
If we replace copper wire with aluminium wire , then resistivity will change .
Hence , since the wire remains made of copper , resistivity will not change.
Answer:
= 85.7 ° C
Explanation:
For this exercise we will use the calorimetry heat ratios, let's start with the heat lost by the evaporation of coffee, since it changes from liquid to vapor state
Q₁ = m L
Where m is the evaporated mass (m = 2.00 103-3kg) and L is 2.26 106 J / kg, where we use the latent heat of the water
Q₁ = 2.00 10⁻³ 2.26 10⁶
Q1 = 4.52 10³ J
Now the heat of coffee in the cup, which does not change state is
Q coffee = M
(
-
)
Since the only form of energy transfer is terminated, the heat transferred is equal to the evaporated heat
Qc = - Q₁
M ce (
-
) = - Q₁
The coffee dough left in the cup after evaporation is
M = 250 -2 = 248 g = 0.248 kg
-Ti = -Q1 / M
= Ti - Q1 / M 
Since coffee is essentially water, let's use the specific heat of water,
= 4186 J / kg ºC
Let's calculate
= 90.0 - 4.52 103 / (0.248 4.186 103)
= 90- 4.35
= 85.65 ° C
= 85.7 ° C
Answer:
(a) ΔP=0.0245 kPa
(b) P=9.14 kPa
(c)ΔP=0.0245 kPa
Explanation:
(a) As it is perfect gas we can use
(P₁V₁)/T₁=(P₂V₂)/T₂
Since this constant volume so
P₁/T₁=P₂/T₂
T₂ is change in temperature
T₂=1.00+273.16
T₂=274.16 K

ΔP=6.71449-6.69
ΔP=0.0245 kPa
(b) As

(c) Same steps as in part (a)

ΔP=9.164-9.14
ΔP=0.0245kPa
-- Coal
-- Oil
-- Natural gas
-- Falling water
-- Sunlight
-- Nuclear fission of Uranium