CRAC Class B (2025) — Questions 881–890
Unofficial study reference only. Not affiliated with the FCC, NCVEC or CRAC — official sources prevail. 非官方学习参考，与 FCC、NCVEC、CRAC 无隶属关系；以官方发布为准。
U0596. The unit of electromotive force is:
电动势的单位是：
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电动势 (EMF) is measured in volts (伏/特) (A) — it is a voltage- like quantity. Ampere is current, watt is power, ohm is resistance.
U0597. The unit of voltage is:
电压的单位是：
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电压 (voltage) is measured in volts (伏/特) (A).
U0598. The unit of current is:
电流的单位是：
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电流 (current) is measured in amperes (安/培) (A).
U0599. The unit of resistance is:
电阻的单位是：
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电阻 (resistance) is measured in ohms (欧/姆) (A).
U0600. The unit of impedance is:
阻抗的单位是：
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阻抗 (impedance) is measured in ohms (欧/姆) (A), the same unit as resistance.
U0601. The unit of power is:
功率的单位是：
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功率 (power) is measured in watts (瓦/特) (A).
U0602. The unit of frequency is:
频率的单位是：
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频率 (frequency) is measured in hertz (赫/兹) (A). Henry is inductance, farad is capacitance, coulomb is charge.
U0603. In the legal system of units, the prefix k has the following mathematical meaning and verbal meaning respectively: ("x＾ m" means "x to the power m")
在法定计量单位中，词头k的数学意义和文字含义分别为：（"x ＾m"表示"x的m次方"）
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The prefix k (kilo, 千) means 10³ (A). Milli is 10⁻³, mega is 10⁶, micro is 10⁻⁶ (B/C/D are other prefixes).
U0604. In the legal system of units, the prefix m has the following mathematical meaning and verbal meaning respectively: ("x＾ m" means "x to the power m")
在法定计量单位中，词头m的数学意义和文字含义分别为： （"x＾m"表示"x的m次方"）
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The prefix m (milli, 毫) means 10⁻³ (A). Kilo is 10³, mega is 10⁶, micro is 10⁻⁶ (B/C/D are other prefixes).
U0605. In the system of legal units of measurement, what are the mathematical significance and textual meaning of the prefix M? ('x＾m' denotes 'x to the power of m'.)
在法定计量单位中，词头M的数学意义和文字含义分别为： （“x＾m”表示“x的m次方”）
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The SI prefix M (mega, 兆) represents a factor of 10^6. Option A correctly pairs the mathematical factor 10^6 with the Chinese character 兆. The other options describe micro (微, 10^-6), kilo (千, 10^3), and milli (毫, 10^-3), which are the prefixes μ, k, and m respectively.