Which of the following is not the same as watt?

Question

Examoogle · Accepted Answer

amperes/volt

Explanation: The watt ($W$) is the SI unit of power, representing the rate at which energy is transferred or converted. By definition, $1 	ext{ watt} = 1 	ext{ joule/second}$, and in electrical systems, $P = V 	imes I$ (volt × ampere) and $P = I^2 	imes R$ (amperes squared × ohms).

Working Principle: In an electrical circuit, power is the product of potential difference ($V$) and current ($I$). Since $V = I 	imes R$, substituting this into $P = V 	imes I$ gives $P = I^2 	imes R$. Conversely, $I/V$ represents conductance ($G$), which is measured in siemens, not watts.

Key Formulas: $P = \frac{W}{t}$ — power as energy per unit time; $P = V 	imes I$ — electrical power in terms of voltage and current; $P = I^2 	imes R$ — electrical power in terms of current and resistance

Key Points: Watt is the SI unit of power.; Joule/second is the definition of a watt in mechanical and electrical terms.; Amperes/volt represents Conductance ($G$), which is measured in Siemens ($S$).; Power is a scalar quantity derived from work done over time.

Advantages: Standardized SI unit for power calculation; Easily relates mechanical and electrical energy domains

Applications: Measuring power consumption of household appliances; Rating electrical motors and generators

Additional Info: Option B (amperes/volt) is the unit of Conductance, denoted by G = 1/R, with units Siemens ($S$).. 1 Watt = 1 Volt × 1 Ampere.

Answer: B is correct — amperes/volt represents conductance, whereas the watt is a unit of power.

Exam Tip: Always verify units by dimensional analysis; $P = VI$ yields $(V)(A) = (J/C)(C/s) = J/s$, confirming the identity.

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