WorksheetsElectrical Power Calculations
Total questions: 25
Worksheet time: 50mins
Calculate the power generated as a 20 A current flows through a 10Ω resistor?
2 W
200 W
4000 W
400 W
How much power can be generated from a 20A current flow because of a 1 kV battery?
20 W
20000 W
0.05 W
0.5 W
What is the resistance of a 75 W bulb with 5 A of current flowing through it?
3 Ω
15 Ω
375 Ω
Resistance is futile!
What is the resistance through a 700 mV bulb with a power of 1 kW?
7 Ω
4.9 x 10-4 Ω
7 x 10-4Ω
70 Ω
Calculate the current through a microwave oven that has a power rating of 800W and a potential difference of 230V.
Give your answer to 3 significant figures.
(a)
calculate the power of a kettle that has a potential difference of 230 V and a current 10 A.
Don't include commas or spaces in your answer
(a)
the equation that links power (P), current (I) and potential difference (V) is...
P=I/V
V=IP
I=VP
P=IV
the unit of power is the...
Watt
Joule
Ohm
Newton
power is defined as...
the strength of the current
the rate of energy transfer
energy transferred per Coulomb of charge
the ratio of potential difference across a component to the current through it.
What is the frequency of mains electricity?
50 KHz
250Hz
50 Hz
150 Hz
What is the potential difference of mains electricity?
320 V
230 V
100 V
430 V
Mains electricity is...
an alternating current (a.c.) supply
a direct current (d.c.) supply
a variable current (v.c) supply
a continuous current (c.c) supply
Calculate the power of an appliance that uses 1000 joules of energy in 5 seconds.
100 W
200 W
300 W
400 W
What is the voltage of an appliance if it uses 200 J per second when supplied with a current of 5 A?
10 V
20 V
30 V
40 V
What is the equation for energy transferred in a circuit?
E=IVt
E=tVI
E=tIV
E=IVt
An electric bulb is connected to a 220V generator. The current is 0.50 A. What is the power of the bulb?
0.0023 W
55 W
110 W
440 W
18 kΩ
A battery of 10 volt carries 20,000 C of charge through a resistance of 20 Ω. The work done in 10 seconds is
2 × 10 5 Joule
2 × 10 3 Joule
2 x 10 4 Joule
2 x 102 Joule
2.41 A
2.52 A
2.1 A
0.3333 A
The battery in the drone can store 97.5 kJ of energy.
When the drone is hovering, the power output of the battery is 65.0 W
Calculate the time in seconds for which the drone can hover. (2 sig fig answer with no units).
(a)
The drone battery powers 4 motors in the drone.
Each motor has a resistance of 1.60 Ω when the power input to each motor is 19.6 W
The 4 motors are connected in parallel with the battery.
Calculate the current through the battery in amps. (2 sig fig answer, no unit needed)
(a)
The diagram shows the circuit used to obtain the data needed to plot the current-potential difference graph for a filament lamp.
The potential difference across the lamp is 12.0 V
Calculate the energy transferred by the lamp when 8.5 C of charge flows through the lamp. (Answer to 3 sig fig).
(a)
