Questions Related to fuse

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

A fuse wire of circular cross-section and having diameter of $0.4$ mm, allows $3$A of current to pass through it. But if another fuse wire of same material and circular cross-section and having diameter of $0.6$ mm is taken, then the amount of current passed through the fuse is?

  1. $3$A
  2. $3\times \sqrt{\dfrac{3}{2}}$A
  3. $3\times\left(\dfrac{3}{2}\right)^{3/2}$A
  4. $3\times \left(\dfrac{3}{2}\right)$A
Reveal answer Fill a bubble to check yourself
C Correct answer
Explanation

The current I that a fuse wire can carry is proportional to the radius raised to the power of 1.5 (or diameter to the power of 1.5). Given d1=0.4 and d2=0.6, the ratio is (0.6/0.4)^(3/2) = (3/2)^(3/2). Thus, I2 = 3 * (3/2)^(3/2).

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

what is a fuse ?

  1. Over current protection

  2. low resistance and high melting point wire.

  3. low resistance and low melting point wire.

  4. high resistance and low melting point wire.

Reveal answer Fill a bubble to check yourself
A,D Correct answer
Explanation

Fuses are safety devices that are to be built into our electrical system. If there were no fuses and we operated too many appliances on a single circuit, the cable carrying the power for that circuit would get extremely hot, short circuit, and possibly start a fire. To prevent electrical overloads, fuses are designed to trip or blow, stopping the flow of current to the overloaded cable.
Fuse is a piece of wire of a material with a very low melting point. When a high current flows through the circuit due to overloading or short circuit, the wires gets heated and melts. As a result, the circuit is broken and current stops flowing.
Hence, the fuse element is made of zinc, copper, silver, aluminum, or alloys to provide stable and predictable characteristics.
The fuse must always be connected to the mains and it must be of correct value. For example, a 15-ampere fuse should trip when the current through it exceeds 15 amperes. A 20-ampere fuse should blow when the current through it exceeds 20 amps.

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

What we used to protect the electric circuits from over loading and short circuit ?

  1. capacitance

  2. inductance

  3. fuse wire

  4. filament wire.

Reveal answer Fill a bubble to check yourself
C Correct answer
Explanation

 fuse is the device to protect the electric circuits from over loading and short circuit.
Fuses are safety devices that are to be built into our electrical system. If there were no fuses and we operated too many appliances on a single circuit, the cable carrying the power for that circuit would get extremely hot, short circuit, and possibly start a fire. To prevent electrical overloads, fuses are designed to trip or blow, stopping the flow of current to the overloaded cable.
Fuse is a piece of wire of a material with a very low melting point. When a high current flows through the circuit due to overloading or short circuit, the wires gets heated and melts. As a result, the circuit is broken and current stops flowing. 
Hence, the fuse element is made of zinc, copper, silver, aluminum, or alloys to provide stable and predictable characteristics.
The fuse must always be connected to the mains and it must be of correct value. For example, a 15-ampere fuse should trip when the current through it exceeds 15 amperes. A 20-ampere fuse should blow when the current through it exceeds 20 amps. Hence correct option is C.

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

Complete the following sentences : 

A fuse is a short piece of wire of high .......... and of material of low ..........

  1. resistance, melting point

  2. meting point, resistance

  3. capacitance, melting point.

  4. conductance, melting point

Reveal answer Fill a bubble to check yourself
A Correct answer
Explanation

A  fuse is the device to protect the electric circuits from over loading and short circuit.
Fuses are safety devices that are to be built into our electrical system. If there were no fuses and we operated too many appliances on a single circuit, the cable carrying the power for that circuit would get extremely hot, short circuit, and possibly start a fire. To prevent electrical overloads, fuses are designed to trip or blow, stopping the flow of current to the overloaded cable.
Fuse is a piece of wire of a material with a very low melting point. When a high current flows through the circuit due to overloading or short circuit, the wires gets heated and melts. As a result, the circuit is broken and current stops flowing. 
Hence, the fuse element is made of zinc, copper, silver, aluminum, or alloys to provide stable and predictable characteristics.
The fuse must always be connected to the mains and it must be of correct value. For example, a 15-ampere fuse should trip when the current through it exceeds 15 amperes. A 20-ampere fuse should blow when the current through it exceeds 20 amps.
Hence, A fuse is a short piece of wire of high resistance and of material of low melting point.

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

Complete the following sentences :

A fuse wire is made of an alloy of .......... and ..........

  1. lead, tin

  2. nickel , lead

  3. cadmium, lead

  4. nickel, tin

Reveal answer Fill a bubble to check yourself
A Correct answer
Explanation

A  fuse is the device to protect the electric circuits from over loading and short circuit.
Fuses are safety devices that are to be built into our electrical system. If there were no fuses and we operated too many appliances on a single circuit, the cable carrying the power for that circuit would get extremely hot, short circuit, and possibly start a fire. To prevent electrical overloads, fuses are designed to trip or blow, stopping the flow of current to the overloaded cable.
Fuse is a piece of wire of a material with a very low melting point. When a high current flows through the circuit due to overloading or short circuit, the wires gets heated and melts. As a result, the circuit is broken and current stops flowing. 
Hence, the fuse element is made of zinc, copper, silver, aluminumor alloys to provide stable and predictable characteristics.
The fuse must always be connected to the mains and it must be of correct value. For example, a 15-ampere fuse should trip when the current through it exceeds 15 amperes. A 20-ampere fuse should blow when the current through it exceeds 20 amps.
Hence, A fuse wire is made of an alloy of lead and tin If the current in a circuit rises too high, the fuse wire melts.

Hence correct option is option A.

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

 What is the current through an electrical appliance of rating 5 kW, 200 V and can you use a fuse which is rated 8 A ? 

  1. 25 A, yes

  2. 2.5 A, yes

  3. 25 A, no

  4. 2.5 A, no

Reveal answer Fill a bubble to check yourself
C Correct answer
Explanation

Fuses are safety devices that are to be built into our electrical system. If there were no fuses and we operated too many appliances on a single circuit, the cable carrying the power for that circuit would get extremely hot, short circuit, and possibly start a fire. To prevent electrical overloads, fuses are designed to trip or blow, stopping the flow of current to the overloaded cable.
The fuse must always be connected to the mains and it must be of correct value. For example, a 15-ampere fuse should trip when the current through it exceeds 15 amperes. A 20-ampere fuse should blow when the current through it exceeds 20 amps.
In this case, let us consider a device of power 5 kW, that is, 5000 W and 200 V.

The current through the appliance is given as $I=P/V.$

That is, $I=\dfrac { P }{ V } =\dfrac { 5000 }{ 200 } =25A$.

The fuse of 8 A cannot be used because the current through the appliance is 
greater the fuse rating. When the 25 A current flows through the fuse it will 
blow off and it will not be able to fulfill it purpose.

Hence, a fuse is rated 8 A cannot be used with this appliance.

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

Two fuse wires of same length are rated 5 A and 20 A. Which is the correct ?

  1. both wire will be same thickness.

  2. 20 A wire is more thicker

  3. 5 A wire more thicker

  4. none of these.

Reveal answer Fill a bubble to check yourself
B Correct answer
Explanation

The fuse must always be connected to the mains and it must be of correct value. For example, a 15-ampere fuse should trip when the current through it exceeds 15 amperes. A 20-ampere fuse should blow when the current through it exceeds 20 amps.
As we know, the cross-sectional area of the wires will affect the amount of resistance. Wider wires have a greater cross-sectional area. Water will flow through a wider pipe at a higher rate than it will flow through a narrow pipe. This can be attributed to the lower amount of resistance that is present in the wider pipe. In the same manner, the wider the wire, the less resistance that there will be to the flow of electric charge. When all other variables are the same, charge will flow at higher rates that is, more current through wider wires with greater cross-sectional areas than through thinner wires.
Hence, the 20 A wire is the thicker wire as more amount of current flow through it than the 5 A wire.

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

Which are the correct for fuse wire?
 

  1. High resistance

  2. low resistance.

  3. low melting point.

  4. high melting point.

Reveal answer Fill a bubble to check yourself
A,C Correct answer
Explanation

The electrical resistance of an electrical conductor is the opposition to the passage of an electric current through that conductor. The SI unit of electrical resistance is the ohm $\Omega $.
When the opposition to the passage of an electric current through that conductor is more it is called high resistance and when the opposition to the passage of an electric current through that conductor is less it is called low resistance.
The amount of resistance determines whether the circuit is a good conductor low resistance, or a bad conductor high resistance. 

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

Which one is correct for fuse wire ?

  1. low resistance and low melting point

  2. high resistance and high melting point

  3. high resistance and low melting point

  4. low resistance and high melting point

Reveal answer Fill a bubble to check yourself
C Correct answer
Explanation

Fuses are safety devices that are to be built into our electrical system. If there were no fuses and we operated too many appliances on a single circuit, the cable carrying the power for that circuit would get extremely hot, short circuit, and possibly start a fire. To prevent electrical overloads, fuses are designed to trip or blow, stopping the flow of current to the overloaded cable.
Fuse is a piece of wire of a material with a very low melting point. When a high current flows through the circuit due to overloading or short circuit, the wires gets heated and melts. As a result, the circuit is broken and current stops flowing. 
Hence, the statement is true as the material used for fuse has low melting point.