Answer:
The minimum heat required is 171626 joules.
Explanation:
By First Law of Thermodynamics, the amount of heat (
), in joules, is equal to the change in internal energy of water. The minimum heat required is the sensible heat necessary to heat up the water. That is:
(1)
Where:
- Density of water, in kilograms per cubic meter.
- Volume of water, in cubic meters.
- Specific heat of water, in joules per kilogram-degree Celsius.
- Change in temperature, in degrees Celsius.
If we know that 
, 
, 
and 
, then the minimum heat required is:
The minimum heat required is 171626 joules.
Answer:
a) 20.81 J
b) 8.29 J
Explanation:
V = iR + L di/dt
where
i = a(1-e^-kt)
for large t
i = V/R
i = 24 / 9.4
i = 2.55 A
so
i = 2.55(1-e^-kt)
di/dt = 2.55 k e^-kt
24 = 24-24e^-kt + 6.4(2.55)k e^-kt
24 = 6.4(2.55) k
k = 24 / (6.4 * 2.55)
k = 24 / 16.32
k = 1.47 = R/L
so
i = 2.55(1-e^-(Rt/L))
current is maximum at great t
i max = 2.55 - 0
energy = (1/2) L i^2
E = (1/2)(6.4)2.55^2
E = 20.81 Joules
one time constant T = L/R and e^-(Rt/L) = 1/e = .368
i = 2.55 (1 - 0.368)
i = 2.55 * 0.632
i = 1.61 amps
energy = (1/2)(6.4)1.61^2
E = 8.29 Joules
Answer:
Which of the following types of light cannot be studied with telescopes on the ground?
The Answer is <u>X-rays</u>
Explanation:
Earth’s atmosphere blocks most of the radiation from space preventing some electromagnetic spectrum from reaching the Earth because they are absorbed or reflected by the Earth's atmosphere. Visible light and radio waves get through to telescopes on the ground, while X-rays are absorbed by most molecules in the Earth’s atmosphere making it visible only from above the atmosphere.
<em><u>Some Terms Explained:</u></em>
Telescope: is an optical instrument that makes distant objects appear magnified. The purposes of a telescope are to gather light using either a lens or a mirror and resolve detail. There are two basic types of telescopes, refractors and reflectors.
Visible light: covers the range of wavelengths from 400–700 nanometers.
X-rays: range in wavelength from 0.001–10 nanometers. They are shorter in wavelength than Ultraviolet rays and longer than gamma rays. They will pass through most substances, and this makes them useful to see inside things.
Radio waves: the longest waves, longer than 1 meter they have the lowest energy. It is used for long distance communication.
Radiation can move through empty space . to transfer heat: convection cannot.
