A) 750 m
First of all, let's find the wavelength of the microwave. We have
is the frequency
is the speed of light
So the wavelength of the beam is
Now we can use the formula of the single-slit diffraction to find the radius of aperture of the beam:
where
m = 1 since we are interested only in the central fringe
D = 30 km = 30,000 m
a = 2.0 m is the aperture of the antenna (which corresponds to the width of the slit)
Substituting, we find
and so, the diameter is
B) 0.23 W/m^2
First we calculate the area of the surface of the microwave at a distance of 30 km. Since the diameter of the circle is 750 m, the radius is
So the area is
And since the power is
The average intensity is
The answer to this question is false
Answer:
Explanation:
Given that
Height = h
Radius = R
From energy conservation
At point B
The minimum speed to complete the the circle
So the kinetic energy at point B
Without falling off at the top (point B)
earth still is not solid ... core is molten ... volcanoes, sea is liquid
at v v v beginning was gas ????