Physics 011

 

Chapter 16

 

Practice Problems

 

1

A charge of coulombs is placed at each corner of a square 1 millionth of a meter on a side. The direction of the force on any of the four charges will be outward along the line passing through the center of the square and the charge being considered. What will be the magnitude of the force on each charge? (Express your answer to 2 decimal places using scientific notation in the form 1.22e6 where this would be 1220000.)

 

2

How many protons are required to make up a charge of x10-12C?

 

3

A metal sphere has a radius of 10 cm. electrons are sprayed on 10 square centimeters of the sphere's surface. After 10 minutes, how many electrons are there on each square centimeter?

 

4

Two charged spheres whose center-to-center distance is meters have charges Q1= 50 microC and Q2=35 microC. What is the force between them, to the nearest tenth of a Newton?

 

5

Two point charges Q1 and Q2, respectively, are separated by .3 meters. If the Coulomb force between them is .21 N and Q1= times Q2, what is Q2 to the nearest hundredth of a microC?

 

6

A water droplet of radius meters remains stationary in air.If the electric field of the Earth is 150 N/C, how many excess electron charges must the droplet have? (Express your answer in scientific notation to two decimal places.)

 

7

Two charges are arranged on the x axis so that there is a positive charge of 3.5x10-6 at the origin and a negative charge of -2.5x10-6 located centimeters to its right.To the nearest cm, where on the x axis should a positive charge be placed so that the net force on it is zero?

 

8

A proton is placed between the plates of a charged capacitor so that it experiences an electric force of Newtons. What is the strength of the electric field? (Express your answer in scientific notation to two decimal places.)

 

9

Three identical charges of 50 microC are arranged at the points of an equilateral triangle meters on a side. To the nearest tenth of a Newton, what is the net force on each charge?

 

10

In the previous problem, what is the force that one charge exerts on another?