The heat (Q) developed in an electric circuit can be calculated using the formula: Q = I² . R . t where: » Q is the heat developed, » I is the cerrent, » R is the resistance, and » t is the time. Given: I = 5A(current) R = 20Ω (resistance) t = 30s (time) Substitude these values into the formula; Q =Read more
The heat (Q) developed in an electric circuit can be calculated using the formula:
Q = I² . R . t
where:
» Q is the heat developed,
» I is the cerrent,
» R is the resistance, and
» t is the time.
Given:
I = 5A(current)
R = 20Ω (resistance)
t = 30s (time)
The resistance of a conductor depends on several factors, and it can be determined using Ohm's Law, which states that: R = V/I where: » R is the resistance, » V is the voltage across the conductor, and » I is the current flowing through the conductor. The factors influencing the resistance of a coRead more
The resistance of a conductor depends on several factors, and it can be determined using Ohm’s Law, which states that:
R = V/I
where:
» R is the resistance,
» V is the voltage across the conductor, and
» I is the current flowing through the conductor.
The factors influencing the resistance of a conductor include:
1. Material: Different materials have different resistivities. Resistivity is an inherent property of a material that determines how strongly it resists the flow of electric current.
2. Length: The resistance is directly proportional to the length of the conductor. As the length increases, the resistance also increases.
3. Cross-sectional Area: The resistance is inversely proportional to the cross-sectional area of the conductor. A larger cross-sectional area allows for more current flow and reduces resistance.
4. Temperature: The temperature of the conductor can affect its resistance. In general, as the temperature increases, the resistance also increases. This effect is more pronounced in some materials than others.
The relationship between these factors is given by the formula:
R = ρ L/A
where:
» R is the resistance,
» ρ is the resistivity of the material,
» L is the length of the conductor, and
» A is the cross-sectional area of the conductor.
In summary, the resistance of a conductor depends on its material, length, cross-sectional area, and temperature.
Current will flow more easily through a thick wire compared to a thin wire of the same material when connected to the same source. This is due to the relationship between resistance, current, and the dimensions of the conductor. According to Ohm's Law ( R = V/I ), the resistance (R) of a conductor iRead more
Current will flow more easily through a thick wire compared to a thin wire of the same material when connected to the same source. This is due to the relationship between resistance, current, and the dimensions of the conductor.
According to Ohm’s Law ( R = V/I ), the resistance (R) of a conductor is inversely proportional to its cross-sectional area (A), given a constant resistivity (ρ) and length (L). The formula for resistance is:
R =ρ L/A
Here:
» R is resistance,
» ρ is the resistivity of the material,
» L is the length of the conductor, and
» A is the cross-sectional area.
Since resistance is inversely proportional to the cross-sectional area (A), a thicker wire with a larger cross-sectional area will have lower resistance compared to a thinner wire of the same material and length.
Lower resistance means that the wire offers less opposition to the flow of electric current. Therefore, current will flow more easily through the thicker wire, and it will experience less voltage drop along its length. This is why thicker wires are often used for applications where low resistance and efficient current flow are important, such as in power transmission lines.
Coils of electric toasters and electric irons are often made of an alloy rather than a pure metal for several reasons: 1. Resistance and Heating Properties: Alloys can be designed to have specific electrical resistance and heating properties. The resistance of a material is a crucial factor in the oRead more
Coils of electric toasters and electric irons are often made of an alloy rather than a pure metal for several reasons:
1. Resistance and Heating Properties: Alloys can be designed to have specific electrical resistance and heating properties. The resistance of a material is a crucial factor in the operation of heating elements. Alloys can be engineered to provide the desired resistance, allowing the toaster or iron to generate the appropriate amount of heat for its intended purpose.
2. High Melting Point: Heating elements in toasters and irons can reach high temperatures during operation. Alloys are often chosen because they can have higher melting points than pure metals, ensuring that the heating element remains stable and doesn’t melt or deform under the high temperatures.
3. Durability and Mechanical Strength: Alloys are often more durable and mechanically robust than pure metals. The mechanical strength of the heating element is important to withstand repeated heating and cooling cycles and mechanical stresses.
4. Corrosion Resistance: Alloys can be formulated to be more resistant to corrosion than pure metals. This is important in appliances like toasters and irons that may be exposed to moisture or humidity during use.
5. Cost-effectiveness: Alloys can be designed to provide the necessary properties at a lower cost than using a pure metal with similar characteristics. This consideration is often important in the manufacturing of appliances where cost efficiency is a significant factor.
One common alloy used for heating elements in appliances is nichrome, which is a nickel-chromium alloy. Nichrome has a high melting point, good electrical resistance, and is corrosion-resistant, making it well-suited for heating applications in electric toasters, irons, and other similar devices.
When resistors are connected in parallel, the reciprocal of the equivalent resistance (Req) is equal to the sum of the reciprocals of the individual resistances. The formula for resistances in parallel is given by: 1/Req = 1/R₁ + 1/R₂ + 1/R₃ + . . . For the given situation: 1/Req = 1/100 + 1/50 + 1/Read more
When resistors are connected in parallel, the reciprocal of the equivalent resistance (Req) is equal to the sum of the reciprocals of the individual resistances. The formula for resistances in parallel is given by:
1/Req = 1/R₁ + 1/R₂ + 1/R₃ + . . .
For the given situation:
1/Req = 1/100 + 1/50 + 1/500
Now, let’s calculate Req:
1/Req = 1/100 + 2/100 + 1/500
1/Req = 3/100 + 1/500
1/Req = 15/500 + 1/500
1/Req = 16/500
Req = 500/16
Req = 31.25Ω
So, the equivalent resistance of the electric lamp, toaster, and water filter connected in parallel is 31.25Ω.
Now, if the electric iron is to draw the same current as all three appliances combined, we can use Ohm’s Law ( V= I ⋅R) to find the current (I) through the equivalent resistance:
I = V /Req
I = 220/31.25
I ≈7.04A
Therefore, the resistance of the electric iron connected to the same source is 31.25Ω, and the current through it is approximately 7.04A.
An electric iron of resistance 20 ohm takes a current of 5 A. Calculate the heat developed in 30 s.
The heat (Q) developed in an electric circuit can be calculated using the formula: Q = I² . R . t where: » Q is the heat developed, » I is the cerrent, » R is the resistance, and » t is the time. Given: I = 5A(current) R = 20Ω (resistance) t = 30s (time) Substitude these values into the formula; Q =Read more
The heat (Q) developed in an electric circuit can be calculated using the formula:
Q = I² . R . t
where:
» Q is the heat developed,
» I is the cerrent,
» R is the resistance, and
» t is the time.
Given:
I = 5A(current)
R = 20Ω (resistance)
t = 30s (time)
Substitude these values into the formula;
Q = (5A)² . (20 Ω) . (30s)
Q = 25 A² . 20Ω . 30s
Q = 25 . 20 . 30 J
Q = 15,000 J
Therefore, the heat developed in the electric iron in 30 seconds is 15,000 joules.
See lessOn what factors does the resistance of a conductor depend?
The resistance of a conductor depends on several factors, and it can be determined using Ohm's Law, which states that: R = V/I where: » R is the resistance, » V is the voltage across the conductor, and » I is the current flowing through the conductor. The factors influencing the resistance of a coRead more
The resistance of a conductor depends on several factors, and it can be determined using Ohm’s Law, which states that:
R = V/I
where:
» R is the resistance,
» V is the voltage across the conductor, and
» I is the current flowing through the conductor.
The factors influencing the resistance of a conductor include:
1. Material: Different materials have different resistivities. Resistivity is an inherent property of a material that determines how strongly it resists the flow of electric current.
2. Length: The resistance is directly proportional to the length of the conductor. As the length increases, the resistance also increases.
3. Cross-sectional Area: The resistance is inversely proportional to the cross-sectional area of the conductor. A larger cross-sectional area allows for more current flow and reduces resistance.
4. Temperature: The temperature of the conductor can affect its resistance. In general, as the temperature increases, the resistance also increases. This effect is more pronounced in some materials than others.
The relationship between these factors is given by the formula:
R = ρ L/A
where:
» R is the resistance,
» ρ is the resistivity of the material,
» L is the length of the conductor, and
» A is the cross-sectional area of the conductor.
In summary, the resistance of a conductor depends on its material, length, cross-sectional area, and temperature.
See lessWill current flow more easily through a thick wire or a thin wire of the same material, when connected to the same source? Why?
Current will flow more easily through a thick wire compared to a thin wire of the same material when connected to the same source. This is due to the relationship between resistance, current, and the dimensions of the conductor. According to Ohm's Law ( R = V/I ), the resistance (R) of a conductor iRead more
Current will flow more easily through a thick wire compared to a thin wire of the same material when connected to the same source. This is due to the relationship between resistance, current, and the dimensions of the conductor.
According to Ohm’s Law ( R = V/I ), the resistance (R) of a conductor is inversely proportional to its cross-sectional area (A), given a constant resistivity (ρ) and length (L). The formula for resistance is:
R =ρ L/A
Here:
» R is resistance,
» ρ is the resistivity of the material,
» L is the length of the conductor, and
» A is the cross-sectional area.
Since resistance is inversely proportional to the cross-sectional area (A), a thicker wire with a larger cross-sectional area will have lower resistance compared to a thinner wire of the same material and length.
Lower resistance means that the wire offers less opposition to the flow of electric current. Therefore, current will flow more easily through the thicker wire, and it will experience less voltage drop along its length. This is why thicker wires are often used for applications where low resistance and efficient current flow are important, such as in power transmission lines.
See lessWhy are coils of electric toasters and electric irons made of an alloy rather than a pure metal?
Coils of electric toasters and electric irons are often made of an alloy rather than a pure metal for several reasons: 1. Resistance and Heating Properties: Alloys can be designed to have specific electrical resistance and heating properties. The resistance of a material is a crucial factor in the oRead more
Coils of electric toasters and electric irons are often made of an alloy rather than a pure metal for several reasons:
1. Resistance and Heating Properties: Alloys can be designed to have specific electrical resistance and heating properties. The resistance of a material is a crucial factor in the operation of heating elements. Alloys can be engineered to provide the desired resistance, allowing the toaster or iron to generate the appropriate amount of heat for its intended purpose.
2. High Melting Point: Heating elements in toasters and irons can reach high temperatures during operation. Alloys are often chosen because they can have higher melting points than pure metals, ensuring that the heating element remains stable and doesn’t melt or deform under the high temperatures.
3. Durability and Mechanical Strength: Alloys are often more durable and mechanically robust than pure metals. The mechanical strength of the heating element is important to withstand repeated heating and cooling cycles and mechanical stresses.
4. Corrosion Resistance: Alloys can be formulated to be more resistant to corrosion than pure metals. This is important in appliances like toasters and irons that may be exposed to moisture or humidity during use.
5. Cost-effectiveness: Alloys can be designed to provide the necessary properties at a lower cost than using a pure metal with similar characteristics. This consideration is often important in the manufacturing of appliances where cost efficiency is a significant factor.
One common alloy used for heating elements in appliances is nichrome, which is a nickel-chromium alloy. Nichrome has a high melting point, good electrical resistance, and is corrosion-resistant, making it well-suited for heating applications in electric toasters, irons, and other similar devices.
See lessAn electric lamp of 100 ohm, a toaster of resistance 50 ohm, and a water filter of resistance 500 ohm are connected in parallel to a 220 V source. What is the resistance of an electric iron connected to the same source that takes as much current as all three appliances, and what is the current through it?
When resistors are connected in parallel, the reciprocal of the equivalent resistance (Req) is equal to the sum of the reciprocals of the individual resistances. The formula for resistances in parallel is given by: 1/Req = 1/R₁ + 1/R₂ + 1/R₃ + . . . For the given situation: 1/Req = 1/100 + 1/50 + 1/Read more
When resistors are connected in parallel, the reciprocal of the equivalent resistance (Req) is equal to the sum of the reciprocals of the individual resistances. The formula for resistances in parallel is given by:
1/Req = 1/R₁ + 1/R₂ + 1/R₃ + . . .
For the given situation:
1/Req = 1/100 + 1/50 + 1/500
Now, let’s calculate Req:
1/Req = 1/100 + 2/100 + 1/500
1/Req = 3/100 + 1/500
1/Req = 15/500 + 1/500
1/Req = 16/500
Req = 500/16
Req = 31.25Ω
So, the equivalent resistance of the electric lamp, toaster, and water filter connected in parallel is 31.25Ω.
Now, if the electric iron is to draw the same current as all three appliances combined, we can use Ohm’s Law ( V= I ⋅R) to find the current (I) through the equivalent resistance:
I = V /Req
I = 220/31.25
I ≈7.04A
Therefore, the resistance of the electric iron connected to the same source is 31.25Ω, and the current through it is approximately 7.04A.
See less