The resistance of a wire is given by R = ρL/A, where ρ is resistivity, L is length, and A is cross-sectional area. Copper has a significantly lower electrical resistivity than steel. Therefore, for wires of identical length and cross-sectional area, the copper wire will have lower resistance than the steel wire. The provided answer 'more resistance' appears to contradict standard resistivity values.
14612
Calculate the electrical conductance of a conductor that has a resistance of 0.5 ohms.
Electrical conductance (G) is defined as the reciprocal of electrical resistance (R). The formula is G = 1/R. Given that the resistance is 0.5 ohms, the conductance is calculated as 1 divided by 0.5, which equals 2 Siemens (S). This represents how easily current flows through the material.
14613
If three resistors with values of 2Ω, 4Ω, and 8Ω are connected in a parallel configuration, what is the resulting equivalent resistance of the system?
For resistors connected in parallel, the reciprocal of the equivalent resistance is the sum of the reciprocals of the individual resistances (1/Req = 1/R1 + 1/R2 + 1/R3). In a parallel circuit, the equivalent resistance is always smaller than the smallest individual resistor in the network. Since the smallest resistor is 2Ω, the equivalent resistance must be less than 2Ω.
14614
Which of the following materials is classified as a conductor rather than an insulator?
Nichrome is an alloy of nickel and chromium, which is a good conductor of electricity. It is commonly used in heating elements due to its high resistance. In contrast, paper, diamond, and ebonite are materials with high electrical resistivity, making them effective electrical insulators.
14615
Using Ohm's Law, determine the current in amperes when a potential difference of 18 volts is applied across a 3-ohm resistor.
According to Ohm's Law, V = IR, where V is voltage, I is current, and R is resistance. Rearranging for current gives I = V / R. Substituting the given values, I = 18 V / 3 Ω = 6 A. Therefore, the current is 6 amperes.
14616
If a uniform metallic wire is divided into two separate segments, how is the resistivity of each segment affected?
Resistivity is an intrinsic property of a material, determined by its atomic structure and temperature, rather than its physical dimensions. When a uniform wire is cut into smaller segments, the resistance of each segment changes because resistance depends on length, but the resistivity remains constant for the material. Therefore, the resistivity of each segment is identical to the resistivity of the original wire.
14617
Two electric bulbs rated 25W-220V and 100W-220V are connected in series to a 440V power supply. Which bulb is likely to fuse?
In a series circuit, the voltage across each component is proportional to its resistance. The resistance of the 25W bulb is higher than that of the 100W bulb. When connected to 440V, the voltage drop across the 25W bulb exceeds its rated 220V capacity, causing it to exceed its power rating and fuse, while the 100W bulb receives less than its rated voltage.
14618
What physical parameter is a thermistor primarily designed to detect and measure in an electronic circuit?
A thermistor is a type of resistor whose electrical resistance varies significantly with changes in its temperature. Because of this property, it is widely used in electronic circuits as a sensor to monitor and measure temperature fluctuations accurately.
14619
Which of the listed materials exhibits the lowest electrical resistivity at room temperature?
Electrical resistivity is a measure of how strongly a material opposes the flow of electric current. Among the choices provided, silver has the lowest resistivity, making it the best electrical conductor, followed by copper and aluminium.
14620
What is the configuration of two resistors if they maintain the same potential difference across them?
In a parallel circuit configuration, the voltage (potential difference) across each branch remains identical. Conversely, in a series circuit, the current remains constant through all components, while the potential difference is divided among them based on their individual resistances.
