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Amanda [17]
3 years ago
15

A satellite in geostationary orbit is used to transmit data via electromagnetic radiation. The satellite is at a height of 35,00

0 km above the surface of the earth, and we assume it has an isotropic power output of 1 kW (although, in practice, satellite antennas transmit signals that are less powerful but more directional).Imagine that the satellite described in the problem introduction is used to transmit television signals. You have a satellite TV reciever consisting of a circular dish of radius R which focuses the electromagnetic energy incident from the satellite onto a receiver which has a surface area of 5 cm^2.How large does the radius R of the dish have to be to achieve an electric field vector amplitude of 0.1 mV/m at the receiver?
Physics
1 answer:
Aleksandr-060686 [28]3 years ago
3 0

Answer:

Explanation:

We have the following relation between power, P and intensity, I

I = P/(4*pi*r^2)

= 10^3/(4*pi*(35000*10^3))

= 6.5*10^-14 W/M^2

We also have the following relationship between electric field and electromagnetic radiation thus

I = (ceE^2)/2

Hence E = \sqrt{2I/ce}

substituting the values of I, c and e, we have

7*10^-6 V/m

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Marizza181 [45]

Answer:

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Explanation:

3 0
2 years ago
which of the following describes the principle of conversation of charge? a.charge is created b. a charge can be transferred c.
victus00 [196]
B) in Physics, charge conservation is the principle that the total electric charge in an isolated system never changes. The net quantity of electrical charge, the amount of positive charge minus the amount of negative charge in the universe is always conserved.
7 0
3 years ago
A light-year is the distance that light travels in one year. The speed of light is 3.00 × 108 m/s. How many miles are there in o
Alinara [238K]

Answer:

(a) 5.88\times 10^{12}mi

Explanation:

We have given speed of light c=3\times 10^8m/sec

Given time = 1 year =365 days

We know that in 1 minute = 60 sec

1 hour = 60×60 = 3600 sec

In one day = 24 hour = 24×60×60=86400 sec

So in 365 days = 365×86400=3.1536\times 10^7sec

We know that distance = speed ×time=3.1536\times 10^7\times 3\times 10^8=9.46\times 10^{15}m

We have given that 1 mi = 1609 m

So 9.46\times 10^{15}m=\frac{9.46\times 10^{15}}{1609}=5.88\times 10^{12}miSo option (a) is correct

8 0
3 years ago
A sample of an unknown substance has a mass of 89.5 g. If 345.2 J of heat are required to heat the substance from 285 K to 305 K
Zinaida [17]

Heat gained in a system can be calculated by multiplying the given mass to the specific heat capacity of the substance and the temperature difference. It is expressed as follows:<span>

Heat = mC(T2-T1)
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7 0
2 years ago
Read 2 more answers
To Mr. H's disgust, a 450-g black crow is raiding the recently-filled bird feeder. As Mr. H runs out the back door with his broo
bagirrra123 [75]

Answer:

Actually it's 2.50 m/s, sorry

Explanation:

It is solved by using momentum conservation equation

combined mass of crow and feeder = 450+670=1120 gm

let the recoil speed of feeder be v m/s

Then applying momentum conservation we get;

1120×1.5 = 670×v

v= 2.50 m/s

the speed at which the feeder initially recoils backwards = 2.50 m/s

5 0
3 years ago
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