Electromagnetic waves differ from mechanical waves in that they do not require a medium to propagate . this means that electromagnetic waves can travel not only through air and solid materials bit also through vacuum of space.
Answer:
Answer to #1, is D.
Explanation:
The theory of plate tectonics states that the Earth's solid outer crust, the lithosphere, is separated into plates that move over the asthenosphere, the molten upper portion of the mantle. This is also, a theory with the ring of fire.
Wavelength = speed / frequency.
Wavelength = 3x10^8 m/s / 30 hz
Wavelength = 10 million meters
1/2 wavelength = 5 million meters
(that's about 3,100 miles)
I'm pretty sure the frequency is wrong in the question.
I think it's actually 30 kHz, not 30 Hz.
That makes the antenna about 3.1 miles long.
For the answer to the question above,
<span>To be 0.1 miles away from the check point ,
the car has to travel 1.4 miles OR 1.6 miles. </span>
53 miles = 60 minutes
1.4 miles = 1.4 / 53 X 60 = 1.5849056 minutes OR 95.1 seconds
<span>1.6 miles = 1.6 /53 X 60 = 1.8113207 minutes OR 108.7 seconds
</span>So the answer is <span>95.1s and 108.7s
I hope my answer helped you</span>
Answer:
A) Air
Explanation:
In refrigerator system the compressor will compress the gas at high pressure so that its temperature is too small and if is passed through the air inside the refrigerator.
When this low temperature gas is passed through the air inside the refrigerator then it will extract the heat from the space or air at high temperature and hence it is the source of energy inside the refrigerator.
Heat pumps are used in in cold atmosphere where we require thermal energy to keep the temperature high. Here compressor will work on the gas so that it will absorb the heat from surrounding air and release it to the room or inside space.
So here in both cases the source of energy here is Air which will give heat to the system.