Question 1

-In Figure 8 -1, if the time from point A to H is 60 µs the frequency is .

Accepted Answer

A) 16.7 kHz 
B) 50 kHz 
C) 25 kHz 
D) More information is required to calculate the frequency.

Question 2

The value of a AC sine wave at any instant can be represented by:

Accepted Answer

A) a graph of the voltage or current vs. the angular measurement. 
B) the formula Vi = Vp × sin 0. 
C) a phasor whose angle and magnitude are representative of the AC signal. 
D) all of these.

Question 3

An oscilloscope's volts/division switch is set on 50 mV/div. If the vertical deflection of the oscilloscope's trace is 1.6 division, what voltage is being measured?

Accepted Answer

A) 1.6 mV 
B) 80 mV 
C) 0.008 V 
D) 50 mV

Question 4

One complete sine wave contains 360°.

Accepted Answer

A) True 
 B)False

Question 5

What type of sensor is used by a clamp meter to measure dc current?

Accepted Answer

A) transformer action 
B) Hall -effect 
C) inductive 
D) inverter

Question 6

-Calculate VR1 in Figure 8 -2.

Accepted Answer

A) 21.4 VP 
B) 6.84 VP 
C) 13.7 VP 
D) 13.2 VP

Question 7

Superimposed DC and AC voltages mean the two voltages are combined:

Accepted Answer

A) in series -parallel aiding or opposing. 
B) in series aiding or opposing. 
C) in parallel aiding or opposing. 
D) all of these

Question 8

The AC sine wave varies from zero to its maximum value in accordance with:

Accepted Answer

A) an algebraic function. 
B) a geometric progression. 
C) a trigonometric relationship. 
D) a mathematical formula.

Question 9

Iif you want to test a system for its frequency response you would probably employ a(n)

Accepted Answer

A) arbitrary function generator 
B) swept -frequency oscillator 
C) multifunction singal generator 
D) custom -pattern generator

Question 10

An ac current is inversely proportional to an ac voltage.

Accepted Answer

A) True 
 B)False

Question 11

20 Vrms of alternating current will illuminate a given lamp at the same intensity as 20 V of direct current.

Accepted Answer

A) True 
 B)False

Question 12

The period of a 5 Hz wave form is 200 ms.

Accepted Answer

A) True 
 B)False

Question 13

-What is the approximate peak input voltage to the circuit in Figure 8 -2?

Accepted Answer

A) 20 VP 
B) 14.1 VP 
C) 28.3 VP 
D) 10 VP

Question 14

What is the instantaneous voltage at 42° on a 230 VP sine wave?

Accepted Answer

A) 149 V 
B) 154 V 
C) 115 V 
D) 76.1 V

Question 15

The time required by a 10 V square wave to change from 1 V to 9 V is known as the .

Accepted Answer

A) rise time 
B) pulse width 
C) period 
D) fall time

Question 16

The average value of a rectangular pulse wave is calculated as:

Accepted Answer

A) Vavg = Vbaseline + (duty cycle)× Vp. 
B) Vavg = Vbaseline + Vp. 
C) Vavg = 1.57 Vp. 
D) Vavg = 0.637 Vp.

Question 17

7.07 VPP is approximately equal to 2.5 VRMS.

Accepted Answer

A) True 
 B)False

Question 18

A square wave is a unique form of the rectangular pulse wave in that:

Accepted Answer

A) the duty cycle is 50%. 
B) the positive and negative halves are equal. 
C) the wave is symmetrical. 
D) all of these

Question 19

A 12 VP sine wave equals _ _.

Accepted Answer

A) 8.48 VRMS 
B) 7.64 VAVG 
C) 24 VPP 
D) all of these

Question 20

In a two -resistor series circuit VR1 = 6.5 VRMS and VR2 = 3.2 VRMS. The source voltage is .

Accepted Answer

A) 9.19 VP 
B) 13.7 VP 
C) 9.7 VP 
D) 4.53 VP

Exam 8: Introduction to Alternating Current and Voltage

-In Figure 8 -1, if the time from point A to H is 60 µs the frequency is .

The value of a AC sine wave at any instant can be represented by:

An oscilloscope's volts/division switch is set on 50 mV/div. If the vertical deflection of the oscilloscope's trace is 1.6 division, what voltage is being measured?

One complete sine wave contains 360°.

What type of sensor is used by a clamp meter to measure dc current?

-Calculate VR1 in Figure 8 -2.

Superimposed DC and AC voltages mean the two voltages are combined:

The AC sine wave varies from zero to its maximum value in accordance with:

Iif you want to test a system for its frequency response you would probably employ a(n)

An ac current is inversely proportional to an ac voltage.

20 Vrms of alternating current will illuminate a given lamp at the same intensity as 20 V of direct current.

The period of a 5 Hz wave form is 200 ms.

-What is the approximate peak input voltage to the circuit in Figure 8 -2?

What is the instantaneous voltage at 42° on a 230 VP sine wave?

The time required by a 10 V square wave to change from 1 V to 9 V is known as the .

The average value of a rectangular pulse wave is calculated as:

7.07 VPP is approximately equal to 2.5 VRMS.

A square wave is a unique form of the rectangular pulse wave in that:

A 12 VP sine wave equals _ _.

In a two -resistor series circuit VR1 = 6.5 VRMS and VR2 = 3.2 VRMS. The source voltage is .