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3 years ago

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

ective, the antenna is a circular aperture through which the microwaves diffract. What is the diameter of the radar beam at a distance of 30 km

1 answer:

My name is Ann [436]3 years ago

5 0

Answer:

915m

Hope this helps.

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Describe a technology used in space exploration.

Alex777 [14]

Answer:

High speed optical communication technology

To be able to communicate from the space to the earth and from earth to space is one of the most essential features required during space exploration.

Explanation:

Space exploration involves going into the space, beyond the earth's atmosphere. Landing on other planets and studying their details, going into deeper space beyond the planets to discover new cosmic events or structures is all a part of space exploration.

The key to analyse the studies and observations is being able to communicate the data collected, photos taken etc to the launch centers or space centers on earth. The space centers on earth should also be able to communicate with the persons or the satellites in space.

This is made possible using the optical communication technology which involves the use of optical fibers, lasers etc, since high speeds are more efficient during communication

3 0

3 years ago

A current I flows down a wire of radius a.

Helga [31]

Answer:

(a) $K = \frac{I}{2\pi a}$

(b) $J = \frac{I}{2\pi as}$

Explanation:

(a) The surface current density of a conductor is the current flowing per unit length of the conductor.

$K = \frac{dI}{dL}$

Considering a wire, the current is uniformly distributed over the circumferenece of the wire.

$dL = 2\pi r$

The radius of the wire = a

$dL = 2\pi a$

The surface current density $K = \frac{I}{2\pi a}$

(b) The current density is inversely proportional

$J \alpha s^{-1}$

$J = \frac{k}{s}$ ......(1)

k is the constant of proportionality

$I = \int\limits {J} \, dS$

$I = J \int\limits \, dS$ ........(2)

substituting (1) into (2)

$I = \frac{k}{s} \int\limits\, dS$

$I = k \int\limits^a_0 \frac{1}{s} {s} \, dS$

$I = 2\pi k\int\limits\, dS$

$I = 2\pi ka$

$k = \frac{I}{2\pi a}$

substitute $J = \frac{k}{s}$

$J = \frac{I}{2\pi as}$

7 0

3 years ago

What is the equivalent resistance of a circuit that contains four 75.0 resistors connected in parallel with a 100.0 V battery?

zhannawk [14.2K]

To get the total resistance in a parallel circuit, you need to remember that unlike in a series, you do not just merely add the resistances. You need to get the reciprocal first of each resistance and add them together.

$\frac{1}{R_{T}} = \frac{1}{R_{1}}+\frac{1}{R_{2}}+\frac{1}{R_{3}}... +\frac{1}{R_{n}}$

After adding them, you will get the reciprocal again and then compute for the value. The problem says that there are 4 resistors in the circuit that have a resistance of 75.

$\frac{1}{R_{T}} = \frac{1}{75}+\frac{1}{75}+\frac{1}{75}+\frac{1}{75}$

Add up the numerator and copy the denominator:

$\frac{1}{R_{T}} = \frac{4}{75}$

Then get the reciprocal to get the total resistance:

$R _{T} = \frac{75}{4} = 18.75$

The answer to your question then is A. 18.8.

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4 years ago

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I REALLY NEED HELP

ikadub [295]

The first law of thermodynamics states the conservation of energy and heat where the total energy in an isolated system may be transformed into another, but never created or destroyed. If 286 J of energy was released to the room, then also 286 J of energy was also removed from food in that refrigerator assuming it is an isolated system. :)

Read more on Brainly - brainly.com/sf/question/3844753
I tried to help

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3 years ago

What is the kinetic energy of a jogger with a mass of 65 kg traveling at a velocity of 2.5 m/s?

scZoUnD [109]

KE=203.125 J !!!!!!!!!

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3 years ago

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