5.4 x 1014Hz
wavelength x frequency = the speed of light
Answer:
A. 20 N
Explanation:
the weight of book is 2×10= 20N
1) The wavelength of the radiation emitted by the human skin is

the frequency of the radiation is related to the wavelength by

where

is the speed of light. Plugging numbers into the formula, we find the frequency of the radiation:

2) The frequency of this radiation is 313 GHz, and its wavelength

. If we look at the table of the electromagnetic spectrum
https://en.wikipedia.org/wiki/Electromagnetic_spectrum
We see that we are in the range of visible light (in particular, in the infrared range).
Therefore, the correct answer is <span>2. visible light .</span>
Answer:
a.
b.
c. 
Explanation:
Use Gravitational Force:

Use values given to have the results.
b.

Use m as the mass of the Moon. Using values of a. and m you have the answer.
c.

Use M mass of the planet. Use value of a and Mass of Planet.