Answer:
Explanation:
Let the plastic rod extends from - L to + L .
consider a small length of dx on the rod on the positive x axis at distance x . charge on it = λ dx where λ is linear charge density .
It will create a field at point P on y -axis . Distance of point P
= √ x² + .15²
electric field at P due to small charged length
dE = k λ dx x / (x² + .15² )
Its component along Y - axis
= dE cosθ where θ is angle between direction of field dE and y axis
= dE x .15 / √ x² + .15²
= k λ dx .15 / (x² + .15² )³/²
If we consider the same strip along the x axis at the same position on negative x axis , same result will be found . It is to be noted that the component of field in perpendicular to y axis will cancel out each other . Now for electric field due to whole rod at point p , we shall have to integrate the above expression from - L to + L
E = ∫ k λ .15 / (x² + .15² )³/² dx
= k λ x L / .15 √( L² / 4 + .15² )
Answer:
The answer to your question is: letter D.
Explanation:
a.The mass that a mole of substance has, measured in grams per mole. Density is not measure in moles, so this is not the correct answer.
b.The amount of substance dissolved in a liquid, measured in moles per liter. The substance dissolved in a liquid must be measure in grams not in moles, so this answer is incorrect.
c.The mass of substance dissolved in a liquid, measured in grams per milliliter. I think that this definition is correct but is incomple, so this answer is wrong.
d.The ratio of a substance's mass to its volume, measured in grams per milliliter and also equivalent to grams per cubic centimeter. This is the right description to density, so this is the correct answer.
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 air pressure ( or atmospheric pressure ) is the force of air over a unit of area. Changes in the air pressure causes the weather changes. High pressure usually brings good weather with dry and cool air. But in a low pressure zone warm air is rising up. This vertical movements are caused by winds high in the troposphere. Water molecules stay as a gas in warmer air. After the vertical movement they condense and bring steady continuous rain. Therefore the low pressure brings cloudly and rainy weather. Answer: The air pressure is most likely low<span>. </span>
