Electric Field Strength: 2009 HSC Exam Question Explained | Australia

In summary, the conversation discusses the calculation of electric field strength for a positively charged plate with a voltage of +100V instead of 0V. The formula used is E = V/d, where V represents the difference in volts between the two plates and d represents the distance. The correct calculation for the given scenario is 2000 V/m. A question is also raised about the voltage difference between positively and negatively charged plates in a battery, to which it is clarified that the difference is not 20V but rather +10V relative to the 0V of the negative terminal. The conversation also touches upon the concept of battery operation.
  • #1
123ryoma12
8
1
upload_2015-9-20_16-36-16.png

This is from the 2009 HSC exam. (I'm in Australia)
I checked the answers and found that electric field strength was
E = 100/0.10 = 1000
My question is, what would the electric field strength be if the positively charged plate was +100V instead of 0V
Would it be 200/0.1 = 2000?
Is the formula E = The difference in volts between the two plates / distance.
Please help this has been bugging me.
 
Physics news on Phys.org
  • #2
123ryoma12 said:
E = 100/0.10 = 1000
No it was not. The electric field strength is a dimensionful quantity and you simply cannot quote it as just a number without a unit. The field strength is 1000 V/m = 1 kV/m.

123ryoma12 said:
Would it be 200/0.1 = 2000?
It would be 2000 V/m.
 
  • #3
I just realized that I shouldn't have posted here. Sorry about that.
But another question
http://www.regentsprep.org/Regents/physics/phys03/aparplate/plate3.gif
In this gif where
E = V/d
Shouldn't it be E = 2V/d
as there is voltage going to the positive and negatively charged plate for example
if the battery has 10V
The negatively charged would be -10V and the positively charge would be 10V
 
  • #4
123ryoma12 said:
Shouldn't it be E = 2V/d
as there is voltage going to the positive and negatively charged plate for example
if the battery has 10V
The negatively charged would be -10V and the positively charge would be 10V

why would you think that ?
There isn't a 20V difference across the plates
one terminal of the battery, the positive, is +10V relative to the 0V of the negative terminalDave
 
  • #5
Oh ok thanks. I just thought that for some reason. I didn't really know how the battery worked.
 
  • Like
Likes davenn

1. What is electric field strength?

Electric field strength is a measure of the force exerted on a unit charge by an electric field. It is represented by the symbol E and is measured in newtons per coulomb (N/C).

2. How is electric field strength related to electric potential?

Electric field strength is directly proportional to electric potential, which is the amount of work needed to move a unit charge from one point to another in an electric field. This relationship is expressed by the equation E = V/d, where E is the electric field strength, V is the electric potential, and d is the distance between the two points.

3. How is electric field strength calculated?

Electric field strength can be calculated using the equation E = kQ/r^2, where k is the Coulomb's constant (9x10^9 Nm^2/C^2), Q is the charge creating the field, and r is the distance from the charge to the point where the field is being measured.

4. What is the unit of measurement for electric field strength?

The unit of measurement for electric field strength is newtons per coulomb (N/C).

5. How is electric field strength used in practical applications?

Electric field strength is used in various practical applications, such as in the design of electrical systems, the development of electronic devices, and the study of electricity and magnetism. It is also used in industries such as telecommunications, energy, and medical technology.

Similar threads

Replies
41
Views
3K
Replies
4
Views
849
Replies
3
Views
1K
  • Introductory Physics Homework Help
Replies
1
Views
1K
Replies
21
Views
2K
Replies
7
Views
17K
  • Introductory Physics Homework Help
Replies
4
Views
2K
  • Electromagnetism
Replies
6
Views
4K
  • Electromagnetism
Replies
1
Views
2K
Back
Top