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WorksheetsScience 8 Q1 M7-9: Basic Electricity, Electric Circuit and Safe Electricity Application
Total questions: 15
Worksheet time: 19mins
A motorcycle starter motor needs 40.0 A to operate with a resistance of 0.150 ohms. What is the needed voltage to start the motor?
5.00 V
6.00 V
7.00 V
8.00 V
What is the electric current if a circuit has a resistance of 100 Ω and voltage of 12.0 V?
25.0 A
12.0 A
9.00 A
0.120 A
What type of conducting wire has the greatest resistance to the flow of current?
thin, long wire
thick, long wire
thin, short wire
thick, short wire
Which of the following statements is correct about the relationship of voltage and current?
Current varies directly with voltage and resistance is changing.
Current varies indirectly with voltage and resistance is changing.
Current varies directly with voltage when resistance remains constant.
Current varies indirectly with voltage when resistance remains constant.
What happens to the brightness of the bulbs connected in series when more and more bulbs are added to the circuit?
increases
decreases
remains the same
cannot be predicted
Which of the following is correct, when the resistances of 1.0 Ω, 2.0 Ω and 3.0 Ω are connected in parallel circuit?
The total resistance is less than 1.0 Ω.
The total resistance is greater than 1.0 Ω.
The total resistance is greater than 2.0 Ω.
The total resistance is greater than 3.0 Ω.
The following are true about parallel circuit EXCEPT:
Voltage is constant across the circuit.
Total resistance is less than the smallest resistance in the circuit
Total resistance is greater than the largest resistance in the circuit.
Total current is the sum of current passing through all the loads in the circuit.
If one bulb is damaged in the circuit, other bulbs will still function.
advantage of series circuit
advantage of parallel circuit
disadvantage of series circuit
disadvantage of parallel circuit
Three light bulbs with resistances 2000 Ω, 1600 Ω, and 800 Ω are connected in series respectively. Which one has the highest brightness when the circuit is plugged to a 220 V voltage source?
800 Ω
1600 Ω
2000 Ω
none of the choices
Why is earthing used at home?
to prevent short circuit
to cut the circuit in case of overloading
to reduce the resistance of the appliance
to provide alternative route of upsurge current in case of grounded circuit
The fuse at home has “blown” up many times. Which of the following must NOT be done to solve the problem and prevent it from happening again?
Buy fuse with standard amperage rating.
Do not use all appliances simultaneously.
Call your barangay electrician to fix your electrical problem.
Use jumper wire or cover the blown fuse with available silver paper.
Which of the following directs any excess current in the metal casing of appliances to the ground?
fuse
earthing
circuit breaker
electric sockets
Which of the following statements is NOT true about safety devices used at home?
Safety devices are used to prevent electric shock
Safety devices cut the flow of current in case of overloading.
Safety devices are used to provide alternative route for current in the case of a grounded circuit.
Safety devices supply unsteady amount of voltage to protect appliances against overloading.
Which electrical device blows up when there is overloading in the circuit?
fuse
switch
resistor
circuit breaker
According to Ohm’s law, across a resistor with constant resistance, what happens to the current across it when the voltage applied is halved?
halved
doubled
quadrupled
remains the same
