With reference to electric are welding:

(a) Draw a labeled sectional sketch of a satisfactory butt weld. (6)

(b) Briefly define the following defects that may occur and how they may have been (6)

(i) Under cut

(ii) Splatter

(iii) Inclusion

(iv) Blow hole

(v) Incomplete root penetration

(vi) Lack of fusion

(c) Why is alternating current generally more popular than direct current for metal are welding? (4)