A steady current is passing through a conductor of non-uniform cross-s...
Explanation:
Steady Current:
A steady current refers to the flow of charge in a conductor that remains constant over time. In other words, the rate of flow of charge does not change with time. This is achieved by maintaining a constant potential difference (voltage) across the conductor.
Charge Crossing a Cross-section:
When a steady current flows through a conductor, the charge carriers (usually electrons) move in a particular direction. The quantity of charge crossing any cross-section of the conductor per second is known as the current.
Relationship with Area of Cross-section:
The current passing through a conductor is directly proportional to the area of its cross-section. This can be understood by considering the analogy of water flowing through a pipe. If the pipe has a larger cross-sectional area, more water can flow through it per second. Similarly, if the cross-sectional area of the conductor is larger, more charge can flow through it per second.
Relationship with Length of Conductor:
The current passing through a conductor is independent of the length of the conductor. This can be understood by considering the analogy of water flowing through a pipe again. The length of the pipe does not affect the rate at which water flows through it, as long as the cross-sectional area remains the same. Similarly, the length of the conductor does not affect the rate at which charge flows through it, as long as the cross-sectional area remains the same.
Net Quantity of Charge:
Since the current passing through a conductor is directly proportional to the area of its cross-section and independent of the length of the conductor, it follows that the net quantity of charge crossing any cross-section per second is independent of the area of the cross-section. This means that regardless of the size of the cross-section, the same amount of charge will flow through it per second as long as the current remains constant.
Therefore, the correct answer is option 'A': The net quantity of charge crossing any cross-section per second is independent of the area of the cross-section.
A steady current is passing through a conductor of non-uniform cross-s...
Explanation:
When a steady current passes through a conductor of non-uniform cross-section, the net quantity of charge crossing any cross-section per second is independent of the area of cross-section. This is known as the law of conservation of charge.
Law of Conservation of Charge:
According to the law of conservation of charge, the total amount of charge entering a given region must be equal to the total amount of charge leaving that region. In other words, charge cannot be created or destroyed, it can only be transferred from one region to another.
Current:
The current flowing through a conductor is defined as the rate of flow of charge. Mathematically, it is given by the equation:
I = ΔQ/Δt
Where I is the current, ΔQ is the change in charge, and Δt is the change in time.
Net Quantity of Charge Crossing a Cross-Section:
When a steady current passes through a conductor, the net quantity of charge crossing any cross-section per second remains constant. This means that the amount of charge entering a cross-section is equal to the amount of charge leaving that cross-section.
Independence of Area of Cross-Section:
The net quantity of charge crossing a cross-section per second is independent of the area of cross-section. This is because the current remains constant throughout the conductor, regardless of its cross-sectional area.
If the current were directly proportional to the area of cross-section, it would mean that a larger cross-sectional area would result in a larger current. However, this is not the case. The current is determined by the voltage applied and the resistance of the conductor, not the area of cross-section.
Therefore, the correct answer is option 'A' - the net quantity of charge crossing any cross-section per second is independent of the area of cross-section.
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