science in plumbing Flashcards
what is AC
alternating current
what is DC
direct current
what is the symbol for AC
a circle with 2 lines either side and a squiggle in the middle
what is the symbol for DC
2 lines one dotted
what is the equation for ohms law
current x voltage x resistance
what are the four measurements of electrical flow
amps voltage ohms resistance
what is current measured in and what is its symbol
amps-I
what is voltage measured in and what is its symbol
volts-V
what is resistance measured in
ohms
what is power measured in and what is its symbol
watts-W
If an appliance needs 3kW in a domestic property, what
is the fuse size?
12.5 amp.
In a domestic property, an appliance has a fuse size of
3 amp. What is the maximum power rating of the
appliance?
720w or 0.72kW.
An appliance has a 5 amp fuse and needs 1.2kW of
power. What is the voltage required?
240v.
What would be the resistance of a domestic appliance
if the fuse size was 3 amp?
20 ohms
what is the name of the circuit when the neutral and the earth wires don’t meet
TNS
what is the name of the circuit when the neutral and the earth meet
TNCS
what is the name of the circuit when it is just the earth going through an earth rod in the ground
TT
Which of the following is the basic principle behind Newton’s First Law of Motion
an object will remain motionless unless an external force is acted upon it
what is the si base unit for length
meter
which plastic is commonly used for underfloor water mains
MDPE
what is the process of water changing from ice into vapor called
sublimation
what type of corrosion occurs due to high flow pressures
erosion corrosion
which gas has a specific gravity less than 1
helium
what is the term for water to be able to flow through a tight space
capillarity
what is the main component of natural gas
methane
