Answer. 30 minutes
Explanation. If he walks 70 m in one minute how long will it take him to walk 2,100 m. Well, this is a simple division problem (you could also use a ratio box).
2100/70= 30. Hope this helps, let me know if it’s correct so others can use it :)
Good luck.
Explanation:
Electromagnetic waves are the waves which are created as the result of the electrical waves which are perpendicular to each other and also perpendicular to the direction of propagation.
Electromagnetic spectrum is range of the frequencies and their respective wavelengths of the various type of the electromagnetic radiation.
In order of the increasing frequency and the photon energy and the decreasing wavelength the spectrum are:
radio waves, microwaves, infrared radiation, visible light, ultraviolet radiation, X-rays and gamma rays.
The energy of the radio waves photons is the lowest of all the other waves in the electromagnetic spectrum.
Also, 
Where,
h is Plank's constant having value 
Thus, energy is directly proportional to the frequency. The radio waves have the lowest frequency.
Answer:
The potential for r > rb is equal to zero.
Explanation:
For r > rb, the potential is:

Then, the net potential is:



Answer:
Explanation:
60000 kJ / h = 60000 x 1000 / (60 x 60 )
= 16667 J /s
a)

where
and
are heat supplied and heat given from outside source .
Here
= 16667 J/s

= 15.684

16667 / W = 15.684
W= minimum power supplied = 1062.7 W.
b )
If 

=19.87



= 838.8 W .