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PHY
PHY 102 EXAM QUESTIONS WITH CORRECT
VERIFIED ANSWERS LATEST UPDATE
(2024/2025) GUARANTEED PASS
Your friends are installing a loft in their room and are using thin speaker
wires to provide power to an extra outlet. If they draw only a small amount
of current from the outlet, the voltage drop in each of the wires will remain
small. Why? - ANS ✓The voltage drop is directly proportional to the current.
Ohm's law states that the potential difference (voltage drop) is directly
proportional to the current.
A particular lightbulb is designed to consume 40 W when operating on a
car's 12-V DC electric power. If you supply that bulb with 12-V AC power
from a transformer, how much power will it consume? - ANS ✓40 W.
The lightbulb will consume the same amount of power it was designed to
consume. The average power of an AC source is the same power provided
as a DC source.
Your toaster consumes 800 W when operating on 120-V AC electric power.
If your rugby team is camping and all of you string together flashlight
batteries to supply that toaster with 120-V DC electric power, how much
power will it consume? - ANS ✓800 W.
PHY 102
, 2
PHY
The toaster will consume the same amount of power it was designed to
consume. The average power of an AC source is the same power provided
as a DC source.
To read the magnetic strip on an ID or credit card, you must swipe it
quickly past a tiny coil of wire. Why must the card be moving for the coil
system to read it? - ANS ✓A moving magnet will induce a current in the coil so
that the magnetic strip can be read.
Only moving magnets or a changing magnetic field will produce the electric
field necessary to push currents through the coil.
If the primary coil of a transformer has 200 turns and is supplied with 120-
V AC power, how many turns must the secondary coil have to provide 12-V
AC power? - ANS ✓20 turns.
secondary voltage = primary voltage · (secondary turns / primary turns)
secondary turns = (secondary voltage / primary voltage) · primary turns
secondary turns = (12-V AC / 120-V AC) · 200 turns
The primary coil of a transformer makes 240 turns around the iron core,
and the secondary coil of that transformer makes 80 turns. If the primary
voltage is 120-V AC, what is the secondary voltage? - ANS ✓40-V AC.
PHY 102
PHY
PHY 102 EXAM QUESTIONS WITH CORRECT
VERIFIED ANSWERS LATEST UPDATE
(2024/2025) GUARANTEED PASS
Your friends are installing a loft in their room and are using thin speaker
wires to provide power to an extra outlet. If they draw only a small amount
of current from the outlet, the voltage drop in each of the wires will remain
small. Why? - ANS ✓The voltage drop is directly proportional to the current.
Ohm's law states that the potential difference (voltage drop) is directly
proportional to the current.
A particular lightbulb is designed to consume 40 W when operating on a
car's 12-V DC electric power. If you supply that bulb with 12-V AC power
from a transformer, how much power will it consume? - ANS ✓40 W.
The lightbulb will consume the same amount of power it was designed to
consume. The average power of an AC source is the same power provided
as a DC source.
Your toaster consumes 800 W when operating on 120-V AC electric power.
If your rugby team is camping and all of you string together flashlight
batteries to supply that toaster with 120-V DC electric power, how much
power will it consume? - ANS ✓800 W.
PHY 102
, 2
PHY
The toaster will consume the same amount of power it was designed to
consume. The average power of an AC source is the same power provided
as a DC source.
To read the magnetic strip on an ID or credit card, you must swipe it
quickly past a tiny coil of wire. Why must the card be moving for the coil
system to read it? - ANS ✓A moving magnet will induce a current in the coil so
that the magnetic strip can be read.
Only moving magnets or a changing magnetic field will produce the electric
field necessary to push currents through the coil.
If the primary coil of a transformer has 200 turns and is supplied with 120-
V AC power, how many turns must the secondary coil have to provide 12-V
AC power? - ANS ✓20 turns.
secondary voltage = primary voltage · (secondary turns / primary turns)
secondary turns = (secondary voltage / primary voltage) · primary turns
secondary turns = (12-V AC / 120-V AC) · 200 turns
The primary coil of a transformer makes 240 turns around the iron core,
and the secondary coil of that transformer makes 80 turns. If the primary
voltage is 120-V AC, what is the secondary voltage? - ANS ✓40-V AC.
PHY 102
