Electromagnetism

Question 1

1. Who made the first battery?
2. What did he use?
3. How was it constructed?

Answer 1

1. Volta
2. Copper and zinc
3. Stacked like a Dagwood sandwich

Question 2

__1__ passed current through a wire and put a __2__ near wire to demonstrate that a __3__ surrounds a wire carrying current.

Answer 2

1. Oersted
2. Compass
3. Magnetic Field

Question 3

Left Hand Rule indicates direction of __1__that surround a current carrying wire. Thumb indicates __2__ of __3__ and fingers demonstrate __4__.

Answer 3

1. Flux lines
2. Direction
3. Current Flow
4. Direction of flux

Question 4

_____=coil of wire

Answer 4

Helix

Question 5

____=helix with a current

Answer 5

Solenoid

Question 6

___=solenoid with ferromagnetic core

Answer 6

Electromagnet

EX: Transformer

Question 7

Ways to induce a current in a wire:
A. Move a ___ over a wire
B. Move a wire through a ____
C. Allow wire to lie in __1__ varying __2__

Answer 7

A. Magnetic field
B. Magnetic field
C. 1. Magnetic field
2. Strength

Question 8

Faraday’s law says that current will be __1__ in a circuit in some part of it is in a __2__

Answer 8

1. Induced

2. Magnetic field

Question 9

Magnitude of induced current in a wire depends on: 
\_\_1\_\_ of magnetic field. 
\_\_2\_\_ of wire as it moves in field. 
\_\_3\_\_ of conductor. 
\_\_4\_\_ of turns in conductor.

Answer 9

1. Strength
2. Velocity
3. Angle
4. Number

Question 10

Transformer is used to vary __1__ & __2__

Answer 10

1. Current

2. Voltage

Question 11

Rectifier converts __1__ to DC. Used in circuit because __2__ operates on DC but EVERYTHING else in circuit uses __3__.

Answer 11

1. AC
2. X-ray tube
3. AC

Question 12

Generator and motor look identical=coil of wire (__1__) located within a magnetic field.

Answer 12

1. Armature

Question 13

Generator=by rotating armature within the magnetic field, a __1__ is induced in __2__

Answer 13

1. Current

2. Armature

Question 14

Motor=placing the charged armature in the __1__ will cause it to rotate due to a once or side __2__ on the wire.

Answer 14

1. Magnetic field

2. Thrust

Question 15

AC Generators and Motors use __1__. DC generators and motors use a __2__.

Answer 15

1. Slip rings

2. Commutator ring

Question 16

Induction motor spins __1__ in the X-ray tube. Stem is __2__ and parallel pairs of electromagnets surrounding rotor are __3__. Speed can be varied.

Answer 16

1. Anode
2. Rotor
3. Staters

Question 17

These motors are used in clocks, ski lifts, ect. Spins at a constant speed.

Answer 17

Synchronous Motor

Question 18

Step up transformer increases voltage and decreases __1__. Used to generate __2__ in a circuit. Less turns on __3__ (thicker) wire and more turns on the __4__ (thinner) wire. Works on AC, __5__ induction.

Answer 18

1. Amp
2. kV
3. Primary
4. Secondary
5. Mutual

Question 19

Step down transformer decreases __1__ and increases __2__. Used to heat __3__ and generate __4__ n X-ray tube. More turns on the __5__ wire and less turns on the __6__. Works on AC, __7__ induction.

Answer 19

1. Voltage
2. Amp
3. Filament
4. MA
5. Primary
6. Secondary
7. Mutual

Question 20

Transformer law

Answer 20

Vs/Vp=Ns/Np

Question 21

Transformer Energy Lossess=Hysteresis, __1__ currents, and __2__ losses. __3__ of the core helps reduce loss.

Answer 21

1. Eddy
2. Copper
3. Lamination

Question 22

Lamination is _____

Answer 22

Layering

Question 23

Air core transformer=simplest type, most __1__, __2__ coils of wire __3__ (AC MUTAL)

Answer 23

1. Inefficient
2. Two
3. Side by side

Question 24

Open core transformer=2 coils with ____ core

Answer 24

Iron

Question 25

Closed core transformer=two coils wrapped around a round or square ____ core

Answer 25

Laminated

Question 26

Shell type transformer=both could wrapped in __1__ of __2__ shaped block __3__ core. MOST __4__ and used __5__.

Answer 26

1. Center
2. Concrete
3. Laminated
4. Efficient
5. Most often

Question 27

Autotransformer=AKA “__1__”. Single wire wrapped around __2__ core. Tapped turns to __3__/__4__ voltage which is supplied to primary side of step up transformer. Works off of AC self induction.

Answer 27

1. KV Selector
2. Single
3. Increase
4. Decease

Question 28

Right hand or __1__ Rule=thumb indicates __2__ of wire, Index indicates __3__ of magnetic field, middle indicates direction of __4__ flow.

Answer 28

1. Motor
2. Motion
3. Direction
4. Current