q-4
a transformer with 20 turns on the primary coil and 1000 turns on the secondary coil an input voltage of 220 v would have and output voltage of
11 kv
if the primary of the high-voltage transformer is supplied by 220 v and has 200 turns and the secondary coil has 100,000 turns, what is the voltage induced in the secondary coil
110 kv
what is the secondary voltage if the primary voltage is 220v in a transformer with a turn ratio of 500:1
110 kv
if a transformer has 120 volts, 16 amps on the primary side with 10/1 ratio what is the voltage on the secondary side
1200 volts
consider a simple transformer that has 100 turn primary coil and 1000 turn secondary coil. the primary side is connected to an electrical device with a resistance of 1000 ohms You have previously calculated the voltage and the current , what is the power in the secondary coil:
1440 watts
what is the velocity of a javelin that travels 45 meters in 3 seconds
15 m/s
how much is the output voltage of a power supply if it supplies 75 w of power while delivering a current of 5 A
15 v
how much is the output voltage of a power supply if it supplies 75w of power while delivering a current of 5A
15a
a traformer for the mammography machine coverts 220v input to 18.33 if the primary coil has 2040 toruns, how many turns does the secondary have
170 turns
determine the voltage on the secondary coil of a transformer if the voltage on the primary coil is 3080v and the ratio of primary turns ti secondary turns us 14:1
220v
an alarm clock that wakes you up to study draws 0.5A of current when connected to an 120v circuit calculate its resistance
240
the primary side of a transformer is connected to a source of voltage that has two components an alternating current (ac) component of 120 volts and steady DC current of 5 volts. the number of turns of the primary side is 300 and the secondary side has 6000 turns what is the voltage on the secondary side 600 volts Dc 2400 volts AC only 2400 volts AC and 100 Volts Dc 100 volts Dc only
2400 volts ac only
A book weighing 1.0 newton falls 2 meters to the floor. how much work was done
2j
A step down transformer has a turn ratio 4 to 1 or 4 if the secondary voltage is 120v determine the primary bold
480v
what is the turn ratio of a transformer which has 120,000 v on the primary side and 2400v on the secondary side
50:1
a circuit contains a series combination of three resistances at 14 21 and 24 resistance respectively. what is the total resistance in the circuit.
60 ohms
how much power is dissipated by 8 ohms load if the current is 10 a
800w
If the primary coil of the high-voltage transformer is supplied by 110 V and has 100 turns, and the secondary coil has 80,000 turns, what is the voltage induced in the secondary coil? (A) 88 V (B) 88 kV (C) 135 kV (D) 135 V
88 kV
an increase in____ will increase both beam quality and beam quantity
kvp
An x-ray unit operating at 249 volts and 20 amperes. what is the power in the unit? 4800watts 57.6watts 4.8 kw 269watts 461 watts
p=VxI 249x20= 4980
Can be either conductor or insulator depending on conditions
semiconductor
looped coil with current flowing through it
solenoid
a transformer has 800 turns on its primary and 600 turns in its secondary side . waht type of transformer is it
step down
the number of turns on a transformer is 450 on the secondary side and 75 on the primary side, what type of transformer is this
step up
open core transformers are most used from of transformers because of their efficiency true false
false
plants absorb energy form light and covert it to mechanical and chemical energy in the form of sugar true false
false
the current used by transformers is direct current true false
false
there is a directed relationship between the quantity of x-rays and the
miliamperage
which of the following devices converts electric energy to mechanical energy?
motor
the basic principle of the transformer is when a current carrying coil is placed near a second coil. a current is induced in the second coil. this principle is called
mutual induction
what material will make a good insulator of electricity? aluminum foil gold wire copper wire plastic
plastic
Electron flow from negative to positive is true false
true
In alternating current flow first in one direction (the first half of the cycle) and then in the other direction ( the second half of the cycle) true false
true
a burn will appear where electricity enters and exits the body true false
true
a circuit board is a collection of many circuit parts on a sheet true false
true
a transformer can step up voltage but in no way can is step up energy power true false
true
closed care transformers are heavily insulated coils wound around a square or circular iron core and the core is laminated true false
true
eddy currents are loops of electrical current induced within conductors by a changing magnetic field in the conductors according to faradays law of induction true false
true
electric charges will move when potential differences exist true false
true
for electricity to flow there must be a complete circuit between the source and the ground true false
true
in a series circuit the current has only one loop to flow through true false
true
in an ideal transformer power in the primary coil is equal power in secondary coil true false
true
in the x-ray circuit, a step down transformer is located in the filament circuit true false
true
magnetic fields can be concentrated by coiling a conductor true false
true
objects can be electrified by induction true false
true
the magnetic field must be changing or fluctuation in order for mutual indication to occur true false
true
the turn ratio is a ratio of secondary turns to primary turns true false
true
transformers can be made up to 99% efficient true false
true
when the secondary coils of a transformer has more turns then the primary side, voltage is steeped up from primary to secondary and current is correspondingly stepped down true false
true 44
when light rays travel from one material to another, the rays may reflect true false
true.
the number of secondary winding of primary
turn ratio
all of the following are true of shell type transformers except it is the most advanced it is used as a commercial or power transformer it has a laminated core very rare today it has two rectangular holes
very rare today
a primary transformer contains 100 turns on the primary side and the secondary has 200 turns the primary coil is connected to a DC AA battery that supplies of 1.5 volts. what would be the voltage across the secondary coil. 12.5 volts 10 volts 20 volts 0 v
0 v
consider a simple transformer that has 100 turn primary coil and 1000 turn secondary coil. the primary side is connected to 1 20-v alternating source. and secondary is connected to an electrical device with a resistance of 1000 ohms what will be the voltage output of the secondary
1200v
if a transformer has 240 volts the primary side and 500/1 turn ratio what is the voltage in the secondary side 1200 120kv 60 120 720
120kv
in a light bulb electric current passes through the resistance wire which is made of tungsten and electrical energy is changed into heat energy and the wire glows white hot. the filament reminds cool and does not produce heat but produces light true false
false
the human body is not a good conductor if electricity true false
False
a small television draws a current of .42A at 120 volts what is the power ratting for the television
50.4 w
in a transformer core coils are usually wrapped around cor materials such as steel: true False
True
a transformer for an electric razor converts a 220 v input to 18.33 on the secondary side, if the secondary current is 3.8a how much current is drawn from the 220v outlet
0.32a
a circuit contains 1.5 volts battery and a bulb with a resistance of 3 ohms. calculate the current
0.5a
consider a simple transformer that has 100 turns primary coil and 1000 turn secondary coil. the primary side is connected to a 120-v alternating source, and the secondary is connected to an electrical device with a resistance of 1000 ohms what current flows in the secondary circuit.
1.2a
lagging loss form continually changing alternating current
hysteresis
A 6 volt battery produces current of 0.5a what is the power in the circuit
3 watts
all of the following are transformer losses EXCEPT resistance hysterisis eddy current copper loss arcing
Arching
in the x ray circuit the auto-transformer is located between the power source and the step up transformer true false
True
Current flows from positive to negative true false
True positive too negative
when the radiographer selects kilo volts on the control panel, which device is adjusted
auto-transformer
electromagnet that protects form an overload
circuit breaker
increasing the resistance in a circuit results in a(n)
decrease in current
A changing magnetic field does not produce an electric field true false
false
A kilowatt-hour (KWH) is the amount of energy consumed in 3 hours at a rate 1 kw true false
false
In a series circuit current is the same at each point in the circuit and when another resistor is added in series the total resistance decreases true false
false
a parallel circuit contains one branch true false
false
any substance that prevents the flow of electrons is a superconductor true false
false
if the primary side of a transformer has a voltage of 120 and the secondary side has a voltage of 60 what type of transformer is this
step down
a device that increases the voltage of an alternating current is called?
step up transformer
zero resistance to low temperature, current will flow continuously once started
superconductor
what resistance would produce a current of 200 amperes with a potential difference of 2000 volts
10 ohms
a bulb of 100w means that it will consume electrical energy at the rage of
100 joules per second
if a circuit is attached to 20 volt battery and has 5 A of current and 4 ohms of resistance. what is the power in the circuit
100w
electrons move freely
conductor
a transformer operates on dc because the magnetic filed within the iron core must continually change true false
false
filaments in light bulbs and x ray tube are made of tungsten due to its low melting point true false
false
in AC current electrons flow in only one direction. true false
false
layers of metal plates decrease the efficiency of transformers and silicon is often used for its high electrical resistance true false
false
lictenberg figures are superficial ferning that occurs after electrical injuries and it never disappears true false
false
on an auto transformer there are three winding and the winding is used as both the primary and secondary coil true false
false
the simplest air core transformer consist of three highly insulated coils of wire lying side by side or next to each other true false
false
transformer are always oil filled and large transformers circulate oil through the winding to remove the heat true false
false
transformer consist of primary coils, secondary coils and iron core true false
false
the rate of rise and fall of a sine wave is called its:
frequency
an example of a conductor, semiconductor and insulator in that order is
gold, silicon, oil
All of the following are configuration of transformers except closed hard core air shell open
hard core
the resistance in a wire decreases as its diameter
increases
motor that drives the anode in an x ray tube
induction
electrons are fixed, no current can
insulator
when all the colors of the rainbow are combined we do not see any particular color of light "white light or black light" true false
False
the idea that electricity flowing through a conductor produces a magnetic field was identified by
Faraday
