Tag: physics

Quizzes (598) Questions (13441)

Questions Related to physics

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

What is immaterial for an electric fuse?

  1. Its length

  2. Its radius

  3. Its specific resistance

  4. Current flowing through it
Reveal answer Fill a bubble to check yourself
A Correct answer
Explanation

Its length is immaterial for an electric fuse fuse is used to avoid danger due to high current if high current is passed through the fuse it burns and disconnect the power supply the thickness of fuse determines how much current can be pass hence fuse of any length can be used but it's thickness should be proper

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

Fuses are connected in ________ to the live wire:

  1. parallel

  2. series

  3. either way

  4. None
Reveal answer Fill a bubble to check yourself
B Correct answer
Explanation

Answer is B.

The live wire and neutral wire, coming from the electric pole, enter a box fitted just outside our house which has a main fuse F1. The fuse is connected in series with the live wire. This is done so because it is only the live wire which has a high potential of 220 volts unlike the neutral wire which carries zero potential.

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

The essential requirements of a fuse wire are ___________.

  1. High resistance and high melting point

  2. High resistance and low melting point

  3. Low resistance and low melting point

  4. Low resistance and high melting point
Reveal answer Fill a bubble to check yourself
B Correct answer
Explanation

The fuse wire is made of zinc, copper, silver, aluminum, or alloys to provide stable and predictable characteristics. Fuse should be of low resistance and low melting point as per the requirement current rating for overcurrent protection.

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.