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WorksheetsForm 5 Chp 2.5 Electrical Energy and Power
Total questions: 18
Worksheet time: 29mins
Name
Class
Date
1.
A lamp changes __________ energy into light energy.
a)
Kinetic
b)
Electrical
c)
Sound
d)
Chemical
2.
What is the unit of electrical power?
a)
watt
b)
volt
c)
ampere
d)
ohm
3.
One megawatt is equivalent to:
a)
102 W
b)
106 W
c)
1024 W
d)
108 W
4.
A bulb of 100 W means that it will consume electrical energy at the rate of:
a)
100 kJ per second.
b)
100 kJ per hour.
c)
100 joules per second.
d)
100 joules per hour.
5.
What will be the current drawn by an electric bulb of 1000 W when it is connected to a source of 220 V?
Remember: I = P/V
Remember: I = P/V
a)
4.55 A
b)
28800 J or 28.8 KJ
c)
80 W
d)
200 W
6.
A current of 4 A flows through a 20 V car headlight bulb. Calculate the electric power.
Remember: I=P/V
Remember: I=P/V
a)
80 W
b)
200 W
c)
2.5 A
d)
4.55 A
7.
Calculate the electric power of an electrical appliance in which 10 A of current is flowing through a resistor of 2 ohms.
Remember: V=IR and P=VI
Remember: V=IR and P=VI
a)
80 W
b)
200 W
c)
2.5 A
d)
22.5 KJ
8.
Calculate the electric power of an electrical appliance of 20 V having a resistance of 10 ohms.
Remember: I=V/R and P=VI
Remember: I=V/R and P=VI
a)
200 W
b)
40 W
c)
2.5 A
d)
79.20 KJ
9.
Calculate the electrical energy consumed when a potential difference of 5 V is applied across a resistor of 2 ohms for 30 minutes.
Remember: V=IR and I=V/R
Remember: V=IR and I=V/R
a)
80 W
b)
200 W
c)
22500 J or 22.5 KJ
d)
4500 J or 4.5 KJ
10.
A current of 0.5 A flows through a resistance of 10 ohms for half an hour. Find the amount of electrical energy consumed by the resistance.
Remember:
V = IR
P = VI
E = Pt
Remember:
V = IR
P = VI
E = Pt
a)
22500 J or 22.5 KJ
b)
4500 J or 4.5 KJ
c)
79.2 W
d)
2.5 A
11.
An electric meter reads 3462 kWh at the end of the month while a month ago it read 3396 kWh. How many units of electrical energy have been comsumed during the month? Find the cost of electrical energy consumed if 1 unit of energy costs $1.20.
a)
66 kWh = 66 units; $79.20
b)
45 kWh = 44 units; $52.80
c)
22.5 kWh = 22.5 units; $27.00
d)
80 kWh = 80 units; $96.00
12.
a pair of 15-watt computer speakers are connected to a 12-volt power supply. what is the electric current running through the speakers?
a)
1.25 A
b)
0.8 A
c)
12.5 A
d)
180 A
13.
A flashlight bulb with a potential difference of 4.5 V across its filament has a power output of 8.0 W. How much current is in the bulb filament?
a)
3.7 A
b)
0.23 A
c)
1.8 A
d)
0.56 A
14.
What is the potential difference across a resistor that dissipates 5.00 W of power and has a current of 5.0 A?
a)
1.0 V
b)
4.00 V
c)
0.20 V
d)
125 V
15.
An electric appliance labelled 80 W.
What does the label means?
What does the label means?
a)
The rate of change of power is 80 W
b)
The rate of change of energy is 80 J/s
c)
The rate of change of current is 80 A
d)
The rate of change of voltage is 80 V
16.
Which of the graphs represents the equation, P = I2R, where P is power, I is current, and R is a constant?
a)
A
b)
B
c)
C
d)
D
17.
An electric appliance is labelled 2 V, 4 W.
How much electrical charges flow through the electric appliance in 9 minutes?
How much electrical charges flow through the electric appliance in 9 minutes?
a)
2 C
b)
8 C
c)
540 C
d)
1 080 C
18.
How much power is dissipated in the resistor when the switch is closed?
a)
0.8 W
b)
1.2 W
c)
7.2 W
d)
30.0 W
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