x Turn on thread page Beta
 You are Here: Home >< Physics

# Potential difference and electric field watch

1. Question:
The potential difference between origin and point P(x,y,z) is given by:
Volts
What's the electric field associated (in V/m) at point P?

If P has position vector: then the magnitude of P will be .
The negative standard derivative of the potential vector will be electric field:

Combining the terms:

2. (Original post by halpme)
Question:
The potential difference between origin and point P(x,y,z) is given by:
Volts
What's the electric field associated (in V/m) at point P?

If P has position vector: then the magnitude of P will be .
The negative standard derivative of the potential vector will be electric field:

Combining the terms:

Firstly, if x, y and z are unknown, how is your magnitude . That would be assuming .

The electric field is defined as, . As is constant, .

Now, in your working you used the derivative, which in this case in wrong. You need to be using partials.

I.e. .

As both y and z are held constant.

Try have a go now. Remember:

3. (Original post by Phichi)
Firstly, if x, y and z are unknown, how is your magnitude . That would be assuming .

The electric field is defined as, . As is constant, .

Now, in your working you used the derivative, which in this case in wrong. You need to be using partials.

I.e. .

As both y and z are held constant.

Try have a go now. Remember:

So, having reviewed partial derivatives a little bit:
I get E=2z+15. Is this all the question asks for?

TSR Support Team

We have a brilliant team of more than 60 Support Team members looking after discussions on The Student Room, helping to make it a fun, safe and useful place to hang out.

This forum is supported by:
Updated: December 31, 2014
Today on TSR

### Negatives of studying at Oxbridge

What are the downsides?

### Grade 9 in GCSE English - AMA

Poll

The Student Room, Get Revising and Marked by Teachers are trading names of The Student Room Group Ltd.

Register Number: 04666380 (England and Wales), VAT No. 806 8067 22 Registered Office: International House, Queens Road, Brighton, BN1 3XE