Electricity I Midterm

Question 1

What is the definition of base?

Answer 1

The repeated factor that is multiplied to obtain a power

Question 2

What is the definition of element?

Answer 2

A substance that cannot be chemically broken down and contains atoms of only one variety

Question 3

What is the definition of compound?

Answer 3

A combination of the atoms of two or more elements

Question 4

What is the definition of atom?

Answer 4

The smallest particle that an element can be reduced to and still maintain the properties of that element

Question 5

What is the definition of substance?

Answer 5

A fundamental or characteristic part or quality

Question 6

What is Matter?

Answer 6

Anything that has mass and occupies space

Question 7

What are the differences between a gas, a liquid, and a solid?

Answer 7

All are states of matter. Gas is a fluid with low density, and high compressibility. Liquid is a fluid with definite volume, but not shape. Solid has definite volume and shape.

Question 8

What is metal is most often used in contacts?

Answer 8

Silver, has the highest conductivity of materials

Question 9

What are the differences between peak, rms, average, and peak to peak values of sine waves?

Answer 9

Peak: max value of either positive or negitive alternation. RMS: effective, value produces same amt of heat in pure resistive circuit as a DC of same value (0.707 times peak value). Peak to Peak: value measured from max positive to max negative alternation

Question 10

What is a code?

Answer 10

A regulation or minimum requirement

Question 11

What are the differences between OSHA, NEMA, and ANSI?

Answer 11

OSHA: federal agency that requires all employers to provide a safe environment for their employees. NEMA: National Electrical Manufacturers Assoc. assists with info and standards for proper selections, ratings, constructions, testing, etc. ANSI: American National Standards Institute. National organization that helps identify industrial and public needs for standards

Question 12

What are the features of a Class B helmet?

Answer 12

Protects agains high-voltage shock and burns, impact hazards, and penetration by falling or flying objects

Question 13

What is the most visible result of an injury?

Answer 13

Blood

Question 14

What are the states of matter?

Answer 14

Gas, liquid, solid

Question 15

What units are used for capacitance?

Answer 15

Farads

Question 16

What are the parts and characteristics of an atom?

Answer 16

Proton, neutron, electron

Question 17

What is the definition of electricity?

Answer 17

The movement of electrons from atom to atom

Question 18

What are the states of produced electricity?

Answer 18

Solar: solar power directly into DCE, hydroelectric, coal, nuclear, natural gas

Question 19

What is the difference between conductors and insulators?

Answer 19

Conductor has very little resistance, allowing electrical flow easily (3 or less valence electrons). Insulator has high resistance, impeding electrical flow. (4 or more valence electrons)

Question 20

What are potential and kinetic energy?

Answer 20

Potential energy is the stored energy a body has due to position, chemical state, or condition. Kinetic is energy of motion

Question 21

What is the proper name for voltage?

Answer 21

Electromotive Force (EMF)

Question 22

How many directions can DC Voltage travel?

Answer 22

1

Question 23

What is current measured in?

Answer 23

Amperage

Question 24

What are the basic characteristics of AC Voltage?

Answer 24

Reverses direction of flow at intervals

Question 25

What is a resistive circuit?

Answer 25

A circuit that only contains resistance (loads)

Question 26

What is an inductive circuit?

Answer 26

A circuit where current lags voltage

Question 27

What is a capacitive circuit?

Answer 27

A circuit where current leads voltage

Question 28

What is the relationship between current and voltage?

Answer 28

Voltage is the pressure that allows for current to flow

Question 29

What is the definition of inductance?

Answer 29

The property of an electric device that opposes a change in current due to its ability to store electrical energy in a magnetic field

Question 30

What is the definition of capacitance?

Answer 30

The ability of a component or circuit to store energy in the form of an electrical charge

Question 31

What is the definition of resistance?

Answer 31

The opposition to current flow

Question 32

Between inductance and capacitance, which leads and which lags on voltage?

Answer 32

Inductive Circuit: I lags E. | Capacitive Circuit: I leads E.

Question 33

What is power expressed in?

Answer 33

Watts

Question 34

What is the definition of Ohm's law?

Answer 34

The relationship between voltage, current, and resistance in a circuit

Question 35

What does it mean to be grounded?

Answer 35

The connection of all exposed noncurrent-carrying metal parts to earth, via a low-resistance path

Question 36

How many paths exist in a series circuit?

Answer 36

1

Question 37

What is the definition of a parallel circuit?

Answer 37

A connection that has two or more components connected so that there is more than one path for current to flow

Question 38

What is always constant in a series circuit and a parallel circuit?

Answer 38

Series: Current, Parallel: Voltage

Question 39

What does total resistance do in a parallel circuit when loads are added?

Answer 39

Total resistance decreases as loads are added in parallel

Question 40

What is the definition of phase shift?

Answer 40

The state when voltage and current in a circuit do not reach their maximum amplitude and zero level simultaneously

Question 41

What is a standard?

Answer 41

An accepted reference or practice

Question 42

What are the different classes of fire estinguishers and what do each do?

Answer 42

``` A: Ordinary combustibles B: Flammable liquids C: Electrical equipment D: Combustible metals K: Commercial cooking grease ```

Question 43

What are the minimum PPE for electrical work?

Answer 43

Gloves, fire retardant clothes, face-shield and goggles

Question 44

What is grounding and when should it be used?

Answer 44

A low-resistance conducting connection between electrical circuits, equipment, and the earth. Always

Question 45

Describe electrical enclosures and what their purpose is?

Answer 45

Housing that protects wires and equipment and prevents injury to personnel from accidental contact with a live circuit

Question 46

How do you calculate total capacitance in series and in parallel?

Answer 46

Ct = C1 x C2 / C1 + C2

Question 47

How do you calculate total inductance in series and in parallel?

Answer 47

P: Lt = L2 x L3 / L2 + L3. S: Lt = L1 + L2 + etc.

Question 48

What is the OHM's law formula?

Answer 48

E / I x R

Question 49

What is the Power formula?

Answer 49

P / E x I