A 5.0-g object carries a net charge of 3.8 micro-Coulomb. It acquires a speed v when accelerated from rest through a potential difference V. A 2.0-g object acquires twice the speed under the same circumstances. What is its charge?

The value is  

Explanation:

From the question we are told that

     The mass of the object is  

     The net charge is  

     The mass of the second object is  

Generally for the first object the potential energy gained at the end of its acceleration is equal to its  kinetic energy

i.e

Here is the velocity of the first object

        is the potential difference through which it is accelerated  

Generally for the second object the potential energy gained at the end of its acceleration is equal to its  kinetic energy

i.e

Here is the velocity of the second object and from the question it is

        is the potential difference through which it is accelerated        

So

=>        

Generally dividing equation 2 by equation 1

=>        

=>        

=>        

=>        

you get 2.3=1.21*\frac{a}2 or 4.6=1.21a or a=3.802 (b)

explanation: