Answer:
the final temperature = 74.33°C
Explanation:
Using the expression Q = mcΔT for the heat transfer and the change in temperature .
Here ;
Q = heat transfer
m = mass of substance
c = specific heat
ΔT = the change in temperature
The heat Q required to change the phase of a sample mass m is:
Q = m
where;
is the latent heat of vaporization.
From the question ;
Let M represent the mass of the coffee that remains after evaporation is:
ΔT =
where;
m = 2.50 g
M = (240 - 2.50) g = 237.5 g
= 539 kcal/kg
c = 1.00kcal/kg. °C
ΔT =
ΔT = 5.67°C
The final temperature of the coffee is:
ΔT
where ;
= initial temperature = 80 °C
= (80 - 5.67)°C
= 74.33°C
Thus; the final temperature = 74.33°C
Answer:
Part a)
V = 15 Volts
Part b)
P = 180 Watt
Part c)
Rate = 720 Watt
Explanation:
Part a)
When battery is in charging then the potential difference of the terminals of cell is given by
here we know that
EMF = 12 volts
i = 60 A
r = 0.050 ohm
now we have
Part b)
Rate of thermal energy dissipated is the energy which is dissipating across the resistor
so here we have
P = 180 Watt
Part c)
Rate at which Energy stored inside the cell is the rate of electrical energy that is converted into the chemical energy
I think it's an hour and a half
Answer:
Seven
Explanation:
The rules for significant digits are:
- Non-zero digits are always significant.
- Zeros between significant digits are also significant.
- Trailing zeros are significant only after a decimal point.
Here, the 2, 4, 9, and 2 are significant because they are non-zero digits.
The first two 0s are significant because they are between significant digits.
The last 0 is significant because it is a trailing zero after a decimal point.
Therefore, all seven digits are significant.