Ohm's Law Questions

• Ohm’s law application (conceptual): If the voltage across a fixed resistance doubles (R is constant and linear), what happens to the current through that resistance?
• Power-supply performance — efficiency and internal loss: Is it correct to say that the efficiency rating of a power supply is determined by its internal power loss (i.e., loss mechanisms set how much of the input becomes useful output)?
• Resistors and heat — desirability of power dissipation: In general-purpose electronics (excluding heaters and special cases), is the heat produced by a resistor a desirable effect, or is it usually an unwanted loss?
• Ohm’s law proportionality — voltage vs. current: Doubling the voltage across a fixed resistor will cut the current by half. Evaluate this statement for a linear (ohmic) resistor.
• Ohm’s law application — computing current: For a linear resistor, the current through it can be found by dividing the voltage across it by its resistance value. Assess this statement.
• Ohm’s law proportional change — repaired stem: In a fixed-resistance DC circuit, the current is initially 8 mA. If the current is increased to 24 mA with the same resistance, the source voltage must have tripled. Evaluate this claim.
• General trend — resistance vs. current: In a simple circuit obeying Ohm’s law, increasing the total resistance (with source voltage fixed) will generally decrease the current. Assess this statement.
• Ohm’s law basics — the “voltage drop” across a resistor is simply the potential difference measured between its two terminals. In circuit analysis, is this definition appropriate?
• Foundations — electrical power is defined as the rate of energy transfer (work per unit time), not as “how fast current is flowing.” Evaluate the statement.
• Ohm’s devices — for an ideal ohmic resistor, the current–voltage (I–V) relationship is linear and passes through the origin. Does the claim “current and voltage have a nonlinear relationship” hold for ohmic conductors?
• Resistor value vs. wattage — is a resistor’s numeric resistance (in ohms) directly proportional to its power handling capability (watt rating), or are these independent specifications?
• Energy equivalence — verify the statement: consuming 4 kWh of electrical energy is equivalent to drawing 2000 W of power for 2 hours (energy = power * time).
• Unit scaling — choose the most concise engineering notation for 7,500,000 W (watts) from the following options.
• Ohm’s law calculation — a resistor has 12 V across it and carries 500 µA of current. Compute the resistance value and choose the correct option.
• Thermal design — which resistor specification tends to increase as the physical surface area (size and heat-dissipation area) of the resistor increases?
• Direct Ohm’s law implication — for a fixed-value resistor, if the voltage applied across it increases, how does the current through it change (assuming temperature effects are negligible)?
• Resistor sizing (repaired) — “The power rating for the resistor in the given circuit should be at least ___.” Without the circuit diagram, voltage, current, or resistance values, can we determine the minimum wattage?
• Resistor power rating selection (repaired for solvability): A DC bias resistor in a small-signal amplifier is measured to dissipate about 0.18 W under worst-case conditions. According to good design practice (choose the next higher standard wattage so the resistor does not run at its full limit), the minimum power rating for this resistor should be at least ______.
• Ohm’s law relationship — resistance vs current: In a simple conductor at constant temperature supplied by a fixed voltage, resistance (R) and current (I) are _________.
• Energy–power linkage — unit equivalence: The number of joules used in 1 second is always equal to the number of _______. (Hint: energy per unit time.)