One electron Volt (eV) is equal to 1.6 x 10^-19 Joules. Therefore, 10 eV is equal to 1.6 x 10^-18 Joules. In order to produce 20 Joules of energy from 10 eV photons, we would require 20 x 1/(1.6 x 10^-18) = 1.25 x 10^19 particles. This demonstrates that in the world of particle physics, the Joule is a massive energy unit relative to the commonly used electron Volt.
Answer:
Bowling Ball: weight on Earth = 49 N
Textbook: Mass = 2 kg; weight on the moon = 3.2 N
Large dog: weight on Earth = 490 N; weight on the moon = 80 N
Law of Universal Gravitation: 
= gravitational force (Newtons/N)
<em>G</em> = gravitational constant, 6.67430 × 10¹¹ 
<em>m</em>₁ and <em>m</em>₂ = masses of two objects (kilograms/kg)
<em>r</em>² = square of distance between centers of the two objects (meters/m)
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It is B because the other ones are good.
Both believe that an atom contains negative charges and positive charges.
But both were different in the placement of charges