Tag: electric current and its effects
Questions Related to electric current and its effects
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True
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False
Fuses should be connected to the neutral wire.T his statement is false fuses should be connected to live wire.
Fuses used in a household generally have a rating of:
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500A
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5A
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30A
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220A
Fuses used in household generally have a rating of 5A to prevent fuse to melt and prevent circuit to break.
If a fuse is rated as 8 A, and current more than 8 A passes through it then
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it would melt
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circuit gets broken
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both
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none
The maximum current which can flow through a fuse without melting it is called its rating.for example a fuse rated at 8A,can stand current upto 8 A. If current higher than 8 A flows through the fuse, it would melt and circuit gets broken the rating of a fuse depends upon the thickness of the fuse wire (because length of the wire is fixed). The thicker fuse has higher rating. So, the thickness of the fuse wire in 8 A circuit is more than that of the fuse wire in 5 A circuit.
Material used in fuse wire must have
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high melting point
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low melting point
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high resistance
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none
A fuse is a piece of thin wire of a material having low melting point, high resistance. It is based in heating effect on current.
Fuse wire is made up of
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Alloy
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Mixture
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Metals
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Non metals
Fuse is generally made up of an alloy of tin and lead. It is used in series with an appliance to prevent it from damage when excessive flows through the appliance. Material to be used in fuse wire must have Low melting point, low boiling point and high electric resistance.
Mark the correct statement about the material to be used in fuse wire.
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Low melting point
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Low boiling point
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High electric resistance
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All
Fuse wire has
Mark the correct reason why a fuse is always connected in series
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When fuse melts, it breaks down the entire home circuit and no current flows
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In series connection the current for the entire house pass through the fuse
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Both
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None
A fuse is always connected in series because
Which of the following is the function of MCB in household circuit?
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This switches automatically turn off when current exceeds safe limit
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This switches automatically turn on when current exceeds safe limit
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Saves the electrical appliances from getting damaged due to excess current
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Saves from shortcircuiting
An MCB functions by interrupting the continuity of electrical flow through the circuit once a fault is detected. In simple terms MCB is a switch which automatically turns off when the current flowing through it passes the maximum allowable limit.
What is MCB in household circuit connection?
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Micro Circuit Breakers
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Miniature Circuit Breakers
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Miniature Circuit Builders
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Mega Circuit Blockers
An MCB or miniature circuit breaker is an electromagnetic device that embodies complete enclosure in a molded insulating material.
What is/are the advantage of MCB over fuses?
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Its wire melts unlike fuses wire
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It automatically turn off to save from excess electricity
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It takes less time to break the circuit as compare to fuse while overloading
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None of these
- MCB is more sensitive to current than the fuse. It detects any abnormality in the current flow and automatically switches off the electrical circuit.
- In the case of MCB, the fault zone of the electrical circuit can be easily identified. Faulty circuit trips to the off position. On the other hand in case of the fuse, the complete fuse wire needs to be checked by opening fuse grip for confirming the fault zone.
- With MCB it is very simple to resume to the supply. You just need to push the knob of MCB back to on position. But in case of the fuse, the entire fuse wire needs to be replaced.
- MCB provides a better interface with the help of knob than a fuse. In case of the fuse, the compete for handle needs to be taken care out.
- Handling MCB is electrically safer than handling a fuse.
- MCB is reusable and hence has less maintenance and replacement cost. Whereas a fuse needs to be replaced whenever it goes faulty.