Which statement is not correct?
a. Conductors have a higher conductivity than insulators.
b. Conductors have lower resistivity than insulators.
c. The drift velocity can reach the speed of light in vacuum.
d. The unit of current, the ampere (A), is equivalent to (C/s).
e. Current flows through a resistor from high potential to low potential.
The correct answer and explanation is:
The incorrect statement is: c. The drift velocity can reach the speed of light in vacuum.
Explanation:
- Conductors have a higher conductivity than insulators:
This statement is correct. Conductors, such as metals, allow electrical current to flow easily because they have a high conductivity, which means they provide little resistance to the movement of charge carriers (like electrons). Insulators, such as rubber and plastic, have a low conductivity, meaning they resist the flow of electric current. - Conductors have lower resistivity than insulators:
This is also correct. Resistivity is a property that determines how much a material resists the flow of current. Conductors have low resistivity, meaning they offer minimal resistance to electrical current. Insulators, on the other hand, have high resistivity, making it difficult for current to flow through them. - The drift velocity can reach the speed of light in vacuum:
This is the incorrect statement. The drift velocity of electrons in a conductor is extremely slow, usually on the order of millimeters or centimeters per second, depending on the material and conditions. It cannot approach the speed of light in vacuum. The speed of light in vacuum is approximately 300,000,000 meters per second, which is far greater than the drift velocity of charge carriers in any material. Drift velocity is a result of the applied electric field and is limited by the material’s properties, so it cannot reach such high speeds. - The unit of current, the ampere (A), is equivalent to (C/s):
This statement is correct. An ampere is the SI unit of electric current and is defined as the flow of one coulomb of charge per second. Therefore, 1 A = 1 C/s (Coulomb per second). - Current flows through a resistor from high potential to low potential:
This is correct. In a typical resistor, the current flows from the higher potential side to the lower potential side, in accordance with the convention of electric current direction, which is from positive to negative. This flow is driven by the potential difference (voltage) applied across the resistor.
In summary, the drift velocity cannot reach the speed of light in vacuum, making option c the incorrect statement.