**AC Fundamentals MCQs Part 06**

**101.** The instantaneous value of current ππ΄ at π‘=0.35 πππ will be **20.5 mA.**

**102.** The instantaneous value of current ππ΅ at π‘=0.35 πππ will be –**20.6 mA.**

**103. ** What value of dc voltage will produce the same average power as 150V peak sine wave? **106 V.**

**104.** What current will an ammeter show when connected in series with a 32 ohm load that is dissipating a peak power of 288 W? **2.12 A**.

**105.** A 160 W soldering iron is operated from the 60 Hz power line. The resistance of the soldering iron is** 75.6 ohms.**

**106.** A certain sine wave is expressed as π=sin (4000π‘). The frequency of this sine wave will be **637 Hz.**

**107.** A certain 1-Khz sine wave reaches -70 V at π‘=0.6 ππ , The peak value of this sine wave will be** 118 V.**

- A sine wave of voltage produces a peak current of 12 mA in a 3 KΞ© resistor. The average power dissipated in the resistor will be
**216 W.**

109 In a.c. circuits, the a.c. meters measures** r.m.s values.**

110 Radio frequency choke is air cored to **keep inductive reactance low.**

110 Hot wire ammeters are used for measuring **only a.c.**

112 When π£1=50sinπ,π£2=30sin(π+25Β°) and v2=25sin(πβ90Β°),the resultant of (π£1 +π£2βπ£3) is given by **πππ¬π’π§(π½+ππΒ°)**.

- 12<30Β° in rectangular coordinates can be represented as
**ππ.π+ππ.**

114 270/1.7 Ο can be represented in rectangular coordinates as **πππβπ πππ.**

115 A choke coil is used for controlling current in an **a.c.circuit only.**

116 Ohmβs law (πΈ=πΌπ
) **can be applied to a.c. but after replacing R by Z (impedance).**

117 What frequency is one octave above 110 Hz? **220 Hz.**

118 What frequency is the fourth harmonic of 4 Mhz? **16 Mhz.**

**Questions 119 to 122 refer to data given below:**

A 60 Hz power-line voltage of 120 V is applied across a resistance of 10 ohms.

- The rms current in the circuit is
**12 A**.

220 The frequency of the current will be** 60 Hz.**