WorksheetsChapter 15 Test
Total questions: 47
Worksheet time: 37mins
Electric Work - is the work done by ____________k
Electricity
Ampere
Current
Voltage
Magnitude of Electrical work (W) depends on....
Applied Voltage
Current passed through the object
Time
All of it
Equation for work is.....
W = U x I x b
W = U x I x c
W = U x I x cc
W = U x I x t
Unit for mechanical power is ....
W (watt)
P (power)
F (force)
A (ampere)
Electric power =
(Electric work)/SPACE
(Electric work)/hours
(Electric work)/minutes
(Electric work)/time
If an appliance has a current of 10A and a voltage of 3V, what is the power?
10A - 3V = 7W
10A + 3V = 13W
10A x 3V = 30W
10A x 3V = 300W
If you have an electrical appliance, the resistance is 3Ω，applied voltage is 9V, what is the power?
I = V/R → 9V/3Ω = 3A
3A x 9V = 27W
I = V/R → 9V/3Ω = 4A
4A x 9V = 36W
I = V/R → 9A/3V = 3A
3A x 9V = 27W
I = V/R → 9V/3Ω = 3A
3A x 9V = 29W
Consume
Electrical appliances
Actual power
Rated current
means...
消耗
用电器
实际
功
额定
电
消耗
用电器
实际
功率
额定
电流
消
用电
实际
功率
额定
电流
耗
电器
实际
功率
定
电流
If you have an electrical appliance, the resistance is 5Ω，applied voltage is 15V, what is the power?
Current = 15V / 5Ω = 3A
P = VI = 15V × 3A = 54W
Current = 15V / 5Ω = 3A
P = VI = 15V × 3A = 40W
Current = 15V / 5Ω = 3A
P = VI = 15V × 3A = 55w
Current = 15V / 5Ω = 3A
P = VI = 15V × 3A = 45W
1 kiloWatt =
1000A
1000W
1000
10W
100 kW =
10 MW
0.101 MW
0.1 MW
100.100 MW
50 W =
5 mW
5000 mW
500 mW
50000 mW
Which is an electrical appliances?
Joule's law is ...
the heat produced by an electric current i flowing through a resistance R for a time t is proportional to i2Rt.
the heat produced by an electric shock flowing through a plastic
the cold air produced by an electric current
the heat produced by an electric current proportional to i2Rt.
Definition of Thermoelectric effect is ...
when a sports car
is directly converted to electric voltage and vice versa.
when a temperature difference
is not directly converted to wind energy.
when a bird
is converted to electric voltage and vice versa.
when a temperature difference
is directly converted to electric voltage and vice versa.
What is an electric heater?
It is:
• an mechanical device
• that converts
• an electric current
• into heat.
It is:
• an electrical device
It is:
• an electrical device
• that converts
• an electric current
• into heat.
It is:
• an electrical device
• that lives on
cold air
The heating element inside every electric heater,
is an
electrical resistor.
electrical drone
mechanical resistor.
speeding device.
Identify the heating device.
What is meant by heating effect of electric current?
When electric water passes through a conductor.
When an electric current passes through a water line and becomes cold and soft after some time.
When an electric current passes through a conductor, (wire)
and produces popcorn.
When an electric current passes through a conductor, (wire) the conductor becomes hot after some time
and produces heat.
What is thermal effect of electric current ?
The greater the resistance in the wire to the flow of current, the greater the heat.
The smaller the resistance in the wire
to the flow of current.
The wider the resistance flow of current, the greater the heat.
The thinner the wire to the flow of current, the greater the heat.
What are the factors affecting the heat, due to electric current?
Amps of the conductor “R”
1.Resistance of the conductor “R”
2.Intensity (strength) of the current “I”
3.Time of the flow of the current “t”
Time of the flow of the current “t”
Intensity (strength) of the current “I”
1 watt =
10Joule / sec
100Joule / sec
0.1 Joule / sec
1 Joule / sec
1 kW =
10 Joules / sec
1000 Joules / min
1000 Joules / sec
1 Joules / sec
Formula for Joule's Law
Q = I2 x R x s
Q = I2 x R - t
Q = I x R x t
Q = I2 x R x t
The heat generated by the electric heater = Work - Q = W
Current through resistance wire…
Electric heater – 220V
Resistance 55 Ω
I = V/R
= 220 V/55 Ω
= 40 A
I = V/R
= 220 V/55 Ω
= 0.4 A
I = V/R
= 220 V/55 Ω
= 4 A
I = V/R
= 220 V/55 Ω
= 4.4 A
Calculate the following…
Electric heater – 220 V circuit / Resistance wire is 24 Ω / Time working is 8 min
Work out the amount of heat generated
The heat generated by the electric heater in 8 minutes is - 975,052.8 A
The heat generated by the electric heater in 8 minutes is - 975,052.8 W
The heat generated by the electric heater in 8 minutes is - 975,052.8 V
The heat generated by the electric heater in 8 minutes is - 975,052.8 J
A circuit containing a battery of 12V and a heater of resistance 6.0Ω.
1. Calculate the current in the heater.
2. State the name of the particles that flow through the heater.
3. Draw an arrow to show the direction of flow of these particles through the heater.
Name 7 main pieces of information that needs to appear on an electricity bill.
What do we call this device in the picture?
Transformer
Generator
Electric device
Electric meter
WHAT IS: Rated Voltage / (Voltage Rating)?
It is:
• minimum voltage
It is:
• the Maximum voltage
• at which the electrical meter
• can operate safely.
It is:
• the Maximum ampere
It is:
• the Maximum voltage
• at which the voltmeter
• can operate safely.
WHAT IS: Current Rating?
It is:
•the amount
•of voltage
•the electric meter can absorbs.
It is:
•the amount
•of current
•the dog and cat can absorbs.
It is:
the amount
of current
in a wire
It is:
•the amount
•of current
•the electric meter can absorbs.
What is: Electrical Energy Meter Constant?
It is:
a siren in the background.
It is:
red and yellow flashing lights.
It is:
flowing flashes.
It is:
the number of times
§the indicator light
of the energy meter
flashes for every 1kW-h consumed.
How do we calculate electrical energy?
W = P - t
W = P x t
W = P + t
W = P / t
Calculate the below electricity usage sum…
Present reading = 65439 kWh
Previous reading = 63258 kWh
2182 kWh
2172 kWh
2181 kW
2282 kWh
Calculate the following cost…
•P = 900 W
•T = 22 min
•Cost = 0.17 cents
•
•Step 1 - Convert W to kW
•Step 2 – Determine number of kWh
•Step 3 – Determine cost
What is a Household circuit?
It is an electrical system
that controls
the flows of electricity
at our house .
It is an electrical system
that feeds us .
It is an electrical system
that controls
the human being.
It is an electrical system
that are wasted energy .
Components of a Household Circuit includes the following....
Popcorn maker
Bicycle rides
1 x switch
4 x erasers
Power line
Electric Meter
Fuse
Distribution Box
Trip Switch
1 x laptop
2 x wires
3 x conductors
What safety measures are in place in electric circuits?
Electrical grounding.
Fuses.
Circuit breakers
Conductors.
Wires.
Diamonds.
Dogs.
Cats.
Bunnies.
People.
Horses.
Children.
Explain what is a life wire in electricity...
Explain what is a ground wire in electricity...
Explain what is a neutral wire in electricity...
What is Short-circuiting?
When the live wire and the neutral wire come into direct contact
When a fire occurs.
When 2 wires runs parallel.
When a light bulb switches on.
Identify this device...
Design to open the circuit when current exceed the desire limit.
The symbol for.....
Wires connecting
Fuse
Thermal Circuit Breaker
Danger wires
What can you see in this picture?
Magic
4 x Strips
Metal forces
Bimetallic strip
A Thermo-magnetic circuit breaker....
Employs both thermal and magnetic current sensors.
Is a fuse with a strip
Works with batteries
Looks alike
I will pass the final exam
Yes
No
