The answer 1 is
The best-known use of radio waves is for communication; television, cellphones and radios all receive radio waves and convert them to mechanical vibrations in the speaker to create sound waves that can be heard.Electromagnetic radiation is transmitted inwaves or particles at different wavelengths and frequencies.
the answer 2 is
Radio Waves: Instant Communication
Microwaves: Data and Heat
i think the answer number 3 is
It is all about wavelength versus tunnel diameter. The wavelength of GPS is about 20cm it would happily propagate in any normal tunnel if it could get in but the earth and other structures absorb it. AM radio (600kHz - 1500kHz) cannot propagate in any normal tunnel because the wavelength is too long (500m-200m) relative to the diameter, and thus gets reflected at the entrance. FM (100MHz ~ 3m) would propagate and it does for a while but then it suffers reflections
Visual aids are tools that help to make an issue or lesson clearer or easier to understand and know (pictures, models, charts, maps, videos, slides, real objects etc.). ... Visual aids are those devices which are used in classrooms to encourage students learning process and make it easier and interesting.
Explanation:
Given,
- m = 100 kg
- g = 10 N/kg¹
- h = 60 m
- t = 20 s
To Find:
a) Work done by the pump
b) Potential energy stored in the water
c)Power spent by the pump
d)Power rating of the pump.
Solution:
We know that,
- f = 100 kg * 10N/kg
- d = 60 m
[The unit'll be joule since N×M = J]
- b) Potential energy stored in the water
- m = 100 kg
- g = 10N/kg
- h = 60
- same condition here as well, N×M = J
- c) Power of the Pump
- where P = Power; W = Work done & T = Time taken
- As we got the value of work done on question (a),& ATQ time taken is 20 S.
- d) Power rating of the pump = 3 kW
Assumption: The pump is 100% efficient & works well.
36/12= 3 3 IS THE AMOUT OF HALFLIVES
ONE HALF LIFE = 300
TWO HALF LIFE = 150
THREE HALF LIFE = 75
*Divide 600 three times
Gravitational forces are stronger over shorter distances, and
weaker over longer distances. That's a big part of the reason
why our bodies are attracted to the Earth with more force than
we're attracted to Jupiter, for example.
The force doesn't just get weaker in proportion to the distance.
It gets weaker in proportion to the SQUARE of the distance.
