Chapter 21

Question 1

Electric field

Answer 1

• vector field
• generated by the SCD
• exists independently of the test charge (thus E = F/q)
• force per unit charge that a hypothetical positive point charge would experience at posisiton r

Question 2

Steps to calculate E of CCD

Answer 2

1. Divid CCD into inifinetesimal small secgemts of which E is known
2. write down expression for dE
3. superposition principle: integrate dE to add up contributions

Question 3

What consistancy check can we perform on E results for CCDs

Answer 3

-far away from CCD, E should be approx that of a point charge ( x»a)

Question 4

At what distance for charged ring is E the strongest

Answer 4

-Somewhere in the middle, close to charges the E is strong but large cancellations veritcally, far away little cancellationbut far away 1/r dependency, thus somewhere in the middle

        x = a/sqrt(2)

Question 5

An example of planar symmetry

Answer 5

the field of an infinte charged plate/sheet

Question 6

Types of symmetry

Answer 6

• planar
• cylindrical
• spherical