Homework # 20 Electric Field Strength & Voltage Handout Problems: 1. A positive charge of 8.0 x 10 7 C experiences a force of 0.04 N when located at a certain point in an electric field. What is the electric field strength at that point? 2. What is the magnitude of the force exerted on an electron in a uniform electric field whose intensity is 1000 N/C? 3. It takes 4 x 10 3 J of work to move a positive charge of 2 x 10 5 C from one point of an electric field to another. What is the difference of potential between the two points? 4. Two parallel metal plates have opposite charges and a difference of potential of 1000 V between them. (a) How much work in electronvolts is done in moving an electron from the negatively charged plate to the positively charged plate? (b) What is this work in joules? 5. A negatively charged oil drop weighing 9.6 x 10-14 N is balanced between two oppositely charged plates in the Millikan apparatus when the difference of potential between the plates is 300 V and the distance between them 0.010 m. What is the electric field strength between the plates? 6. For the previous question, calculate the charge on the drop. Calculate how many excess electrons are on the oil drop