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3 years ago

10

Why are there shadows?

2 answers:

Deffense [45]3 years ago

6 0

Shadows are formed when an opaque object or an object that doesn't allow light to pass through is in the way or infront of etc. a source of light.

lubasha [3.4K]3 years ago

4 0

It is shown when you are covering the light. So like when the sun is shining down at you, you are standing so the stuff behind you is not getting light because you are in its way.
HOPE THIS HELPS!!!!!!! ;-)

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The visible spectrum refers to the tiny portion of the electromagnetic spectrum that we ________.

marusya05 [52]

Answer:

are able to see/observe

Explanation:

Humans are not able to see most wavelengths in the universe--but there is a select range that is visible to our eyes. This (which is usually shown on an electromagnetic spectrum diagram/chart/depiction by a small portion of rainbow) is the visible light spectrum

3 0

1 year ago

A radar for tracking aircraft broadcasts a 12 GHz microwave beam from a 2.0-m-diameter circular radar antenna. From a wave persp

NISA [10]

A) 750 m

First of all, let's find the wavelength of the microwave. We have

$f=12GHz=12\cdot 10^9 Hz$ is the frequency

$c=3.0\cdot 10^8 m/s$ is the speed of light

So the wavelength of the beam is

$\lambda=\frac{c}{f}=\frac{3\cdot 10^8 m/s}{12\cdot 10^9 Hz}=0.025 m$

Now we can use the formula of the single-slit diffraction to find the radius of aperture of the beam:

$y=\frac{m\lambda D}{a}$

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

$y=\frac{(1)(0.025 m)(30000 m)}{2.0 m}=375 m$

and so, the diameter is

$d=2y = 750 m$

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

$r=\frac{750 m}{2}=375 m$

So the area is

$A=\pi r^2 = \pi (375 m)^2=4.42\cdot 10^5 m^2$

And since the power is

$P=100 kW = 1\cdot 10^5 W$

The average intensity is

$I=\frac{P}{A}=\frac{1\cdot 10^5 W}{4.42\cdot 10^5 m^2}=0.23 W/m^2$

4 0

3 years ago

Charge: A piece of plastic has a net charge of +2.00 μC. How many more protons than electrons does this piece of plastic have? (

snow_lady [41]

Answer

given,

net charge = +2.00 μC

we know,

1 coulomb charge = 6.28 x 10¹⁸electrons

1 micro coulomb charge = 6.28 x 10¹⁸ x 10⁻⁶ electron

= 6.28 x 10¹² electrons

2.00 μC = 2 x 6.28 x 10¹² electrons

= 1.256 x 10¹³ electrons

since net charge is positive.

The number of protons should be 1.256 x 10¹³ more than electrons.

hence, +2.00 μC have 1.256 x 10¹³ more protons than electrons.

6 0

3 years ago

Please list them from top to bottom, for exp like in your response, a,g,q,d. Giving quite some points for it.

Aleks04 [339]

D,f,g,h,i,a,e,c,j. I’m sure that it

7 0

2 years ago

Homeostatasis will be most affected by the romoval of the

Lady bird [3.3K]

I would say D. Hope I helped!

3 0

3 years ago

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