Tag: physics

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

Electric fuses is a _____________ to electrical circuits.

  1. safety device which prevents damages

  2. device which causes damage and fire

  3. simple device which pass current

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

A fuse is an electrical safety device (a component) that removes electrical current from an electrical circuit when the current in the electrical circuit is too high.

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

Which wire could be used as a fuse wire?

  1. Nichrome wire

  2. Zinc

  3. Copper

  4. Silver
Reveal answer Fill a bubble to check yourself
B,C,D Correct answer
Explanation

The fuse element is made of zinc, copper, silver, aluminum, or alloys to provide stable and predictable characteristics. The fuse ideally would carry its rated current indefinitely, and melt quickly on a small excess.

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

Fuse wire is a wire of

  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

A fuse wire must melt and break the circuit when current exceeds a safe limit. To do this effectively, it needs high resistance (to generate heat quickly) and a low melting point (to melt before other components).

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

A fuse is a short piece of wire of .............. and ................?

  1. high resistance, low melting point

  2. high resistance, high melting point

  3. low resistance, low melting point

  4. low resistance, high melting point
Reveal answer Fill a bubble to check yourself
A Correct answer
Explanation

A fuse wire has a HIGH resistance & LESS melting point. so that it can protect the electric appliances at home by undergoing melting due to excess heat produced because of high resistance. 

as a result circuit is not  complete so no current flow in it.
fuse wire have high resistance so that it can handle large magnitude of currents and it have low  melting point so that it can easily melt and break the circuit due to flow of accidentally high magnitude of currents.

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

Fuse has ..... and .....?

  1. high resistance, high melting point

  2. high resistance, low melting point

  3. low resistance, high melting point

  4. low resistance, low melting point
Reveal answer Fill a bubble to check yourself
B Correct answer
Explanation

Melting point of a fuse wire is low. So by any chance if high current flows through the circuit, the fuse melts because of heat produced in the circuit beyond a permissible limit. A fuse must have high resistance so as to oppose the current flowing through it beyond a safe limit.

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

two identical fuses are rated at 10 A , if they are joined

  1. in parallel, the combination acts as a fuse of rating 20 A

  2. in parallel, the combination acts as a fuse of rating 5 A

  3. in series , the combination acts as a fuse of rating 10 A

  4. in series, the combination acts as a fuse of rating 20 A
Reveal answer Fill a bubble to check yourself
A Correct answer
Explanation

When two identical fuses are joined in parallel, the total current capacity is the sum of the individual ratings because the current splits between them. Thus, 10 A + 10 A = 20 A.

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

Two identical fuses are rated at $10\space A$. If they are joined

  1. in parallel, the combination acts as a fuse of rating $20\space A$

  2. in parallel, the combination acts as a fuse of rating $5\space A$

  3. in series, the combination acts as a fuse of rating $10\space A$

  4. in series, the combination acts as a fuse of rating $20\space A$
Reveal answer Fill a bubble to check yourself
A,C Correct answer
Explanation

A fuse is a type of low resistance resistor that acts as a device to provide over-current protection, of either the load or source circuit.
Where several fuses are connected in series, it is desirable to blow (clear) only the fuse (or other over-current device) electrically closest to the fault. Hence, when two fuses are in series the current rating is simply the current rating of each fuse i.e. in series, the combination acts as a fuse of rating 10 A
When two fuses are in parallel the current rating is simply twice the current rating of each fuse, hence, in parallel, the combination acts as a fuse of rating 20 A.

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

What is immaterial for an electric fuse wire

  1. Specific resistance of the wire

  2. radius of the wire

  3. length of the wire

  4. current flowing through the wire
Reveal answer Fill a bubble to check yourself
C Correct answer
Explanation

The heating effect of a fuse wire is primarily determined by its resistance, which depends on its radius and material. The length is generally considered immaterial in basic fuse physics problems.