## electric field line patterns for point charges and parallel plates

These short video clips show how to draw electric field lines for point charges and parallel plates.

## electricity and energy revision questions

Here are questions from Standard Grade and Intermediate 2 that are appropriate revision for the electricity and energy unit of national 5.  Answers to follow.

## nat5 – work, power and potential energy

We’ve been looking at work and the rate of change of energy.  This handout will help you to revise the key points and introduces gravitational potential energy.

## Pressure

If we know the size of the force (F) and the area over which the force is applied (A), then we can calculate pressure using

$P = \displaystyle {F \over A}$

Here is the outline of a pupil’s shoe, it’s drawn on graph paper so that the area can be calculated quickly by counting the large squares.  Each large square is 1 square centimetre – we counted the approximate area by considering only whole squares inside the black outline of the shoe.

Assuming a mass of 50kg, the pressure when wearing these flat-soled shoes is

$P = \displaystyle {{(50 \times 9.8)N} \over {0.0306m^2}} = 16000Nm^{-2}$

The red shaded area of our photo shows the reduction in area when heels are worn.  With heeled shoes, the area is reduced to approximately 1 square cm per shoe.  The change in the pressure is staggering:

$P = \displaystyle {{(50 \times 9.8)N} \over {(0.0002)m^2}} = 2450000Nm^{-2}$

The Science Babe has made a video on this topic.

## national 5 summary notes for electricity & energy unit

Here are summary notes to help you prepare for the upcoming unit assessment.
Thanks to Mr Noble for sharing his notes!

## national 5 exam questions from electricity & energy unit

Here are questions from Standard Grade and Intermediate 2 that are appropriate revision for the electricity and energy unit of national 5.  Answers to follow.