Answer:
<h2>Electricity has many uses in our day to day life. It is used for lighting rooms, working fans and domestic appliances like using electric stoves, A/C and more. All these provide comfort to people. In factories, large machines are worked with the help of electricity.</h2>
The correct options are:
D
"Radio waves have a lower frequency, which makes them safer for humans."
B
"Radio waves take less energy to produce."
<h3>
Why do we radio waves over other electromagnetic waves to transmit information to Earth? </h3>
Radio waves are electromagnetic waves with frequencies on the range from 10 KHz to 10 THz.
Now, remember that all electromagnetic waves have the same speed, which is the speed of light, and the energy of a wave is proportional to its frequency.
Particularly, we can see that radio waves have small frequencies (smaller than infrared light) so these waves carry very little energy.
With that in mind, the correct options are.
D
"Radio waves have a lower frequency, which makes them safer for humans."
B
"Radio waves take less energy to produce."
These are the two main reasons of why we use radio waves.
If you want to learn more about electromagnetic waves.
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Answer:
Answer:
Bus travels 160 km in 4 hours
Speed of bus = 160/4 = 40 km/hr
Train travels 320 km in 5 hours
Speed of train = 320/5 = 64 km/hr
In one hour, bus travels 40 km and train travels 64 km.
Ratio = 40:64 = 5:8
Answer:
electrons
Explanation:
The total charge Q is the sum of the charge of the N electrons contained in the sphere:
charge of a electron
We solve to find N:
