Self-Test: Electrostatics Test #2 
Suggested Time: 75 minutes

Which of the following best illustrates the electric field between parallel plates with opposite electric charges?

A. B.
C. D.



Which of the following diagrams shows the electric field between two equal but opposite charges?


The atomic nucleus of uranium contains 92 protons. What is the direction and magnitude of the electric field 2.5 ×10-10 m from this nucleus?


A 0.16 C charge is moved in an electric field from a point with a potential of 25 V to another point with a potential of 95 V. How much work was done to move this charge?

A. 4.0 J B. 11 J C. 15 J D. 19 J
5. A positively charged oil droplet is in a vertical electric field.

Which of the following is a correctly labelled free-body diagram showing the forces acting on the oil droplet?

A. B. C. D.

What are the magnitude and direction of the electric field between the plates in the situation shown below?





In an experiment, a positively charged oil droplet weighing 6.5 10-15 N is held stationary by a vertical electric field as shown in the diagram.


If the electric field strength is 5.3 103 N/C, what is the charge on the oil droplet?  

A. 1.2 10-18 C B. 3. 4 10-11 C C. 4.1 104 C D. 8.2 1017 C

A proton with kinetic energy of 2.110-17 J is moving into a region of charged parallel plates. The proton will be stopped momentarily in what region?


A. Region K B. Region L C. Region M D. Region N
9. What is the magnitude and direction of the electric field at point P due to the two fixed charges? 



A moving proton has 6.4 10-16 J of kinetic energy. The proton is accelerated by a potential difference of 5000 V between parallel plates.



The proton emerges from the parallel plates with what speed?

A. 8.8 105 m/s B. 9.8 105 m/s C. 1.3 106 m/s D. 1.8 106 m/s
11. What is the electric potential at point P due to the two fixed charges as shown? 


A. 1 200 V B. 1500 V C. 5200 V D. 7100 V
12. An electron in the electric field has an electric force acting on it in what direction?

A. North B. South C. East D. West

A proton initially at rest is accelerated between parallel plates through a potential difference of 700 V.

What is the maximum speed reached by the proton?

A. 8.6 104 m/s B. 3.1105 m/s C. 3. 7 105 m/s D. 1.6 106 m/s



What are the magnitudes of the electric field and the electric potential at point P midway between the two fixed charges?



Which pair of values will cause the greatest deflection of an electron beam in a cathode ray tube?


In a cathode ray tube,

A. protons are accelerated from anode (positive) to cathode (negative).

B. protons are accelerated from cathode (negative) to anode (positive).

C. electrons are accelerated from anode (positive) to cathode (negative).

D. electrons are accelerated from cathode (negative) to anode (positive).


a) Find the electric potential at point A and at point B.  (3 marks)


b) What is the potential difference between A and B? (1 mark)

c) 0.036 J of work must be done to move a charge q from A to B. Find the magnitude and polarity of this charge.    (3 marks)



A beam of electrons is directed to a region between oppositely charged parallel plates as shown in the diagram below.


a) The electron beam is produced by accelerating electrons through an electric potential difference of 380 V. What is the speed of the electrons as they leave the 380 V plate? (3 marks)

b) What is the electrostatic force on electrons in the region between the horizontal plates when they are connected to a 9.0 V potential difference? (3 marks)

c) What is the velocity of the electrons (magnitude and direction) when they exit the second set of plates?(6 marks)

19. A proton, initially at rest at point X, will have what speed at point Y? (7 marks) 



A student decides to investigate how electric field varies along the line connecting two positive point charges. Charge Q2 is greater than charge Q1.

Using principles of physics, describe the electric field along the line from Q1 to Q2 . (4 marks)


21. A charge q of 30.0 mC is moved from point X to point Y. 

How much work is done on the 30.0 mC charge? (7 marks)

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