The answer is A i think from the options though the answers are worded a bit weird
0.01742919 is the answer because i worked it out
Explanation:
The given data for case (1) is as follows.
h = 20 cm = 0.2 m
Assuming that a rectangular slab is placed above the pipe and we will calculate the heat transfer as follows.
Q =
where, A = area
L = length
k = thermal conductivity = 0.8 W/m
= change in temperature.
Therefore, putting the given values into the above formula as follows.
Q =
=
= 168 W
For case (2), h = 180 cm = 1.8 m
Therefore, heat lost will be calculated as follows.
Q =
=
= 18.67 W
Thus, we can conclude that 18.67 W heat lost if the pipe was buried at a depth of 180 cm.
Answer:
2.0x10¹⁷ Hz is the frequency of the X-ray
Explanation:
We can find the frequency of a wave of energy from the wavelenght and its speed using the formula:
v = λƒ
<em>Where v is speed (For electromagnetic radiation = 3.0x10⁸m/s)</em>
<em>λ is the wavelength in meters = 1.5x10⁻⁹m</em>
<em>And f is the frequency in s⁻¹ = Hz</em>
<em />
Replacing:
3.0x10⁸m/s = 1.5x10⁻⁹m*ƒ
3.0x10⁸m/s / 1.5x10⁻⁹m = f
f =
<h3>2.0x10¹⁷ Hz is the frequency of the X-ray</h3>
<em />
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