RAD Ch 5

When considering the Transformer Laws is the power assumed to be the same on both the primary and secondary sides of a transformer?

Yes

What is the process called by which on atoms become aligned and this turn an object into a magnet?

Magnetic induction

The magnetic field lines of an electromagnet are most concentrated

Inside the solenoid

For a step up transformer, the secondary____ is higher/more and the secondary _______ is lower/less than in the primary.

None

turns, currents

voltage, current

b and c

current, voltage

voltage, current

A transformer has 220,000 turns on the secondary winding and 200 turns on the primary winding if 220 V is supplied to the primary side what is the voltage on the secondary side

242 kV

A coil of wire with no core is called

a solenoid

An autotransformer consists of a single core with multiple taps that make the secondary voltage tunable.

false

A step down transformer must have direct current in order to step up the voltage.

false

Outside a magnet the lines of force go from the North pole to the South pole

true

If a DC voltage is applied to the primary coil of a transformer and then doubled, the secondary voltage will

do nothing

if the turns ratio of a transformer is less than 1 it is a _____ transformer

Step down

Which of the following is not one of the three main causes of transformer inefficiency

Magnetic resonance

which of the following elements is not ferromagnetic

lead

A transformer has an electrical potential of 250V on the primary side, 50kV on the secondary side and 5 amps on the secondary side. What is the current in the primary coil

10³ A

*if the turns ratio of 1/10, what is the secondary current if 5A is supplied to the primary?

0.5 A

A current in a wire will induce a magnetic field around a wire

Amperes Law

positioning an iron core in the middle of a current carrying solenoid creates

an electromagnet

Which of the folowing is the most often used power transformer due to its efficiency?

a shell type

An electron in orbit about a nucleus creates magnetic field lines ______ motion

perpendicular to the plane of

in nonmagnetic materis, the magnetic forces are canceled out because the electrons

are paired and spin in opposite directions

what is the electric power resulting from 220 V and 30A supplied to the primary of a transformer that has 220,000 turns on the secondary winding and 200 turns on the primary

6.60 kW

220 volts is supplied to the auto transformer, if a 1000 output is needed, and the primary side has 1200 turns how many turns must be selected on the secondary side

5,454 turns

The term "moving charge" refers to the movement of

electrons

To make the magnetic feld of a solenoid or electromagnet stronger, one may:

a,b, and c

(increase # of turns, increase current, add ferromagnetic core)

Which of the transformers below is the shelltype?

E

Which of the following is not one of the three principal types of magnet?

self

A magnet cut in half produces two magnets one with north poles only and one with south poles only

false

A generator with a commutator ring will produce what type of current?

pulse direct current

A constantly changing magnetic field can be created by passing AC or DC current through a conductor

false

A motor with a slip ring will produce what type of current?

alternating current

When gripping a wire in the right hand, and with the thumb pointing in the direction of convertional current fow, the fingers of your hand will then curl in the direction of the?

magnetic field lines

A changing magnet field will induce a current in a coil

Faradays law

Magnets can be classified by their origin of magnetism while all material (matter) can be classified by the interaction with an external

magnetic field

The SI unit of magnetic field strength is the

tesla