Tag: electrical fuse and mcb

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Multiple choice physics electric current and its effects electric fuse electrical fuse and mcb fuse

Fuse wire is a

  1. tin-lead alloy

  2. copper-lead alloy

  3. tin-copper alloy

  4. silver-lead alloy
Reveal answer Fill a bubble to check yourself
A Correct answer
Explanation
Fuse wire is made of a tin-lead alloy and not copper because of the following reasons:

1. They have high resistance due to high resistance the wire heats up quickly, when large current flows.

Heating power of wire $P=i^2R$

2. They have low melting point which melts and breaks off the circuit if the current is larger than the safety limit.



In Fuse wire a copper wire can not be used because it has a high melting point. Copper wire will not melt easily when a high electric current passes through it and may harm the electrical appliances attached to it.

Multiple choice physics electric current and its effects electric fuse electrical fuse and mcb fuse

State whether true or false.
When a short-circuit takes place, the fuse wire melts and breaks the electric circuit.

  1. True

  2. False
Reveal answer Fill a bubble to check yourself
A Correct answer
Explanation

Yes,given statement is true, because short-cicuiting is an  excessive current flow in the power source through the short due to which the fuse wire melts and breaks the electric circuit.

Therefore, A is correct option

Multiple choice physics electric current and its effects electric fuse electrical fuse and mcb fuse

A fuse is connected to the

  1. Live wire

  2. Neutral wire

  3. Earth wire

  4. None of these
Reveal answer Fill a bubble to check yourself
A Correct answer
Explanation

Fuses are always connected in series with the components to be protected from overcurrent, so that when the fuse blows (opens) it will open the entire circuit and stop current through the components. A fuse connected in one branch of a parallel circuit, of course, would not affect current through any of the other branches.

Multiple choice physics electric current and its effects electric fuse electrical fuse and mcb fuse

If a fuse is rated as 8 A, and current more than 8 A passes through it then

  1. it would melt

  2. circuit gets broken

  3. both

  4. none
Reveal answer Fill a bubble to check yourself
C Correct answer
Explanation

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.

Multiple choice physics electric current and its effects electric fuse electrical fuse and mcb fuse

Fuse wire is made up of

  1. Alloy

  2. Mixture

  3. Metals

  4. Non metals
Reveal answer Fill a bubble to check yourself
A Correct answer
Explanation

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.