Midterms | Unit 2.3 Electromagnetism

Question 1

He observed that a dissected frog leg twitched when touched by two different metals

Answer 1

Luigi Galvani (1700’s)

Question 2

What were the 2 different metals used by Galvani in observing a dissected frog’s leg?

Answer 2

Brass and Iron

Question 3

He contributed to the development of battery

Answer 3

Alessandro Volta

Question 4

Precursor of modern battery

Answer 4

Voltaic Pile

Question 5

A copper-zinc plate like a Dagwood sandwich

Answer 5

Voltaic Pile

Question 6

What are the modern batteries?

Answer 6

Carbon rod (+) & Zinc cylindrical can (-)

Question 7

Any device that converts some form of energy directly into electric energy

Answer 7

Source of Electromotive Force

Question 8

He demonstrated that electricity could be used to generate magnetic fields

Answer 8

HANS OERSTED (1820)

Question 9

It determines the direction of the magnetic field

Answer 9

Right-Hand Rule

Question 10

A coil of wire

Answer 10

Solenoid

Question 11

A current-carrying coil of wire wrapped around an iron core

Answer 11

Electromagnet

Question 12

Electromagnets intensify the —

Answer 12

Induced magnetic field

Question 13

Advantage of an electromagnet

Answer 13

Magnetic field can be adjusted or turned on & off

Question 14

An electric current is induced in a circuit if some part of that circuit is in a changing magnetic field

Answer 14

ELECTROMAGNETIC INDUCTION

Question 15

Experiments under ELECTROMAGNETIC INDUCTION

Answer 15

Faraday and Oersted Experiment

Question 16

He observed the current in a changing magnetic field

Answer 16

MICHAEL FARADAY

Question 17

He described the first law of electromagnetic induction

Answer 17

MICHAEL FARADAY

Question 18

Changing magnetic field induces current

Answer 18

MICHAEL FARADAY’S EXPERIMENT

Question 19

Faraday’s Law
The magnitude of the induced current depends on four factors:

Answer 19

1. Strength of the magnetic field
2. Velocity of the magnetic field as it moves past the conductor
3. Angle of the conductor to the magnetic field
4. Number of turns in the conductor

Question 20

Under Faraday’s experiment, this measures current

Answer 20

Ammeter

Question 21

Moving or spinning charges induces a magnetic field

Answer 21

HANS OERSTED EXPERIMENT

Question 22

Differentiate Faraday and Oersted’s experiments

Answer 22

Faraday: Magnetic field generates electricity

Oersted: Electricity generates a magnetic field

Question 23

Electromagnetic devices

Answer 23

• Electric motor
• Electric generator
• Transformer (Step up; Step down)
• Induction motor (Rotor; Stator)

Question 24

An electric current produces mechanical motion

Answer 24

ELECTRIC MOTOR

Question 25

Switches the direction of current through the loop

Answer 25

Commutator Ring

Question 26

Mechanical motion produces an electric current

Answer 26

ELECTRIC GENERATOR

Question 27

It changes the intensity of alternating voltage & current

Answer 27

TRANSFORMER

Question 28

Transformer is only applicabke in ---

Answer 28

AC

Question 29

Turns ratio greater than 1

Answer 29

Step-up Transformer

Question 30

A type of motor used with x-rays tubes

Answer 30

Induction motor

Question 31

Induction motor powers the --- of an x-ray tube

Answer 31

Rotating anode

Question 32

Rotating part of an electromagnetic induction motor that is ocated inside the glass enveloper

Answer 32

Rotor

Question 33

Stationary coil windings (electromagnet) situated in the protective housing but outside the glass envelope

Answer 33

Stator

Question 34

Voltage and number of turns are directly proportional

Answer 34

TRANSFORMER LAW

Question 35

Types of transformer

Answer 35

- Closed-core transformer - Shell-type transformer - Autotransformer

Question 36

A square core of ferromagnetic materials built up of laminated layers of iron

Answer 36

Closed-core transformer

Question 37

Reduced energy losses caused by eddy current

Answer 37

Closed-core transformer

Question 38

Has two-closed core

Answer 38

Shell-type transformer

Question 39

Confines more of the magnet field lines

Answer 39

Shell-type transformer

Question 40

More efficient than closed-core

Answer 40

Shell-type transformer

Question 41

Consists of one winding and one core

Answer 41

Autotransformer

Question 42

Autotransformer is a --- transformer

Answer 42

step up

Question 43

Where is the autotransformer located?

Answer 43

Located in the operating console

Question 44

What does the autotransformer control?

Answer 44

controls the kVp

Question 45

Function of electric circuit elements - Inhibits flow of electron

Answer 45

Resistor

Question 46

Function of electric circuit elements - Provides electric potential

Answer 46

Battery

Question 47

Function of electric circuit elements - Momentarily stores electric charge

Answer 47

Capacitor

Question 48

Function of electric circuit elements - Measures electric voltage

Answer 48

Voltmeter

Question 49

Function of electric circuit elements - Measures electric potential

Answer 49

Ammeter

Question 50

Function of electric circuit elements - Turns circuit on and off by providing infinite resistance

Answer 50

Switch

Question 51

Function of electric circuit elements Increases & decreases voltage by fixed amount (AC only)

Answer 51

Transformer

Question 52

Function of electric circuit elements - Variable resistor

Answer 52

Rheostat

Question 53

Circuit elements

Answer 53

Resistor Battery Capacitor Ammeter Voltmeter Switch Transformer Rheostat Diode (DRCRABSTV)