Question

1. Two-point charges Q1= 4.5 UC and Q2=8.5 UC are initially very far apart. They are then brought together with a final separation of 3.5 mm. How much work does it takes ri bring them together?

2. An electron is accelerated from rest through a potential difference of 15V. What is the change in electric potential energy of the electron?

3. In nuclear fission, a nucleus splits roughly in half.

 A. What is the potential 4.00 x 10^-14 m from a fragment that has 59 protons in it? (P=+1.602x10^-15 c)

 B. What is the potential energy of a similarly charged fragment at this distance?

Answer 1

1)

$$W=(9\cdot10^{9})\frac{(4.5\cdot10^{-6})(8.5\cdot10^{-6})}{0.0035}=98.4\ J$$

2)

$$\Delta U=15\ eV=2.4\cdot10^{-18}J$$

3) a)

$$V=(9\cdot10^{9})\frac{(1.602\cdot10^{-19})}{4\cdot10^{-14}}=36000\ V$$

b) the same.