Ch19.3-20 Test MCQ

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Class
G91
G92
G93
Name
    ____________
Which symbol represents an AND gate?
选项1
选项2
选项3
选项4
An incomplete truth table for a NAND gate is shown. What are the values of W, X, Y and Z?
A
B
C
D
A truth table for a type of logic gate is shown. Which type of logic gate is it?
AND
NOR
NOT
OR
This is the truth table for a logic gate. Which symbol represents the logic gate?
选项1
选项2
选项3
选项4
There are two inputs and one output for the combination of logic gates shown. Which truth table represents the operation of this combination of logic gates?
选项1
选项2
选项3
选项4
In the circuit shown, the current from the battery divides equally between the two lamps. Each ammeter reads 6.0A. What is a suitable rating for the fuse in this circuit?
3.0A
6.0A
10.0A
13.0A
Why are electric circuits often fitted with fuses?
Fuses break the circuit if the current is too high.
Fuses only allow the current through in the correct direction.
Fuses return any excess current to earth.
Fuses use up any spare current.
A fuse and a relay each use an effect of an electric current. Which effect of an electric current is used by a fuse and which effect is used by a relay?
A
B
C
D
In this circuit, a component at X automatically protects the wiring from overheating if there is a fault. Which components are suitable to use at X?
a circuit-breaker, a fuse or a switch
only a circuit-breaker or a fuse
only a circuit-breaker or a switch
only a fuse
Two electrical appliances are connected to the mains supply. The cable connected to one appliance includes an earth wire. The cable connected to the second appliance does not need an earth wire. What is a reason for this difference?
One appliance has a metal case, but the other appliance does not.
One appliance is fitted with a fuse, but the other appliance is not.
One appliance is fitted with a switch, but the other appliance is not.
One appliance needs more current than the other appliance.

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