Answer:
t = 4.0 min
Explanation:
given data:
diameter of rod = 2 cm
T_1 = 100 degree celcius
Air stream temperature = 20 degree celcius
heat transfer coefficient = 200 W/m2. K
WE KNOW THAT
copper thermal conductivity = k = 401 W/m °C
copper specific heat Cp = 385 J/kg.°C
density of copper = 8933 kg/m3
charateristic length is given as Lc
Biot number is given as
Bi = 0.0025
As Bi is greater than 0.1 therefore lumped system analysis is applicable
so we have
............1
where b is given as
b = 0.01163 s^{-1}
putting value in equation 1
solving for t we get
t = 4.0 min
Answer:
Because the Sun shines by nuclear fusion, which converts mass into energy as hydrogen turns into helium. ... A typical star that is the source of light and heat for the planets in the solar system.
Explanation:
The time needed to evaporate all the water in the kettle is 1.13 x 10³s.
<h3>What is Power?</h3>
The power is defined as the the ratio of amount of energy produced per unit time.
P =E/t
Energy is in the form of heat gained to evaporate all water in kettle.
E = Q =mL
So, P = mL/t
Substitute mass of water m = 0.5kg, latent heat of vaporization of wate L = 2.26 x 10⁶ J/kg, power P= 10³ W, we have
10³ = (0.5 x 2.26 x 10⁶) /t
t = 1.13 x 10³s
Thus, the time needed to evaporate all the water is 1.13 x 10³s.
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Answer:
Explanation:3rd and last choices