Lecture 1

Question 0

Ac advantages

Answer 0

Sustained at high voltages for long distances. Stepped up or down using transformer. 120V or 240V

Question 1

Difference between ac and dc current

Answer 1

Dc:flow of charge in one direction, fixed polarity, can be steady or vary in magnitude. Loses power over a mile due to decreased voltage drop.

Ac: polarity reverses or alternates, varies in magnitude between polarity reversals

Question 2

Reynolds number

Answer 2

Re= (mean velocity x density x diameter)/viscosity under 2000 is laminar over 2500 is turbulent

Question 3

Electrocution are the blank most common in U.S.

Answer 3

5th

Question 4

Amount of people that die each year from electrical accident

Answer 4

700

Question 5

Amount of residential fires each year from elec.

Answer 5

40000

Question 6

Amount lost on property damage each year

Answer 6

2 billion

Question 7

Hospital patients electrocuted in 1972

Answer 7

1200

Question 8

Injuries and death in hospital in 1971

Answer 8

1600 injuries and 100 deaths