Free Printable Chapter 2a

1.

The relationship between voltage, current and resistance in AC circuits is:

a)

$V=IR$

b)

$V=I^2R$

c)

$R=VI$

d)

$V=I/R$

2.

The algebraic sum of all voltages in a closed loop is zero. This describes:

a)

Ohm’s Law

b)

Kirchhoff’s Voltage Law (KVL)

c)

Kirchhoff’s Current Law (KCL)

d)

Power Law

3.

The algebraic sum of currents at a node equals zero. This describes:

a)

KVL

b)

Ohm’s Law

c)

KCL

d)

Power Factor

4.

In AC circuits, the general voltage equation is:

a)

$V(t)=V_m \sin t$

b)

$V(t)=V_m \sin \omega t$

c)

$V(t)=I^2R$

d)

$V(t)=V_m \cos \omega t$

5.

RMS stands for:

a)

Real Maximum Signal

b)

Root Mean Square

c)

Rated Mean Standard

d)

Required Minimum Signal

6.

When current and voltage are in phase, the load type is:

a)

Inductive

b)

Capacitive

c)

Resistive

d)

Reactive

7.

For a pure resistive load, the power factor value is:

a)

0

b)

0.5

c)

1

d)

−1

8.

For an inductive load, the current:

a)

Leads voltage

b)

Lags voltage

c)

Is equal to voltage

d)

Is zero

9.

Inductive reactance ( $X_L$ ) formula:

a)

$X_L=2\pi f R$

b)

$X_L=2\pi f L$

c)

$X_L=\frac{1}{2\pi f C}$

d)

$X_L=\frac{V}{I}$

10.

Capacitive reactance ( $X_C$ ) formula:

a)

$X_C=2\pi f C$

b)

$X_C=\frac{1}{2\pi f C}$

c)

$X_C=\frac{VL}{I}$

d)

$X_C=R+jL$

11.

For a capacitive load, the current:

a)

Lags voltage

b)

Leads voltage

c)

Is opposite to voltage

d)

Has zero angle

12.

The power that performs real work is called:

a)

Reactive power

b)

Active power

c)

Apparent power

d)

Instant power only

13.

The unit of active power (P) is:

a)

var

b)

VA

c)

W

d)

J

14.

Reactive power (Q) is measured in:

a)

VA

b)

W

c)

var

d)

kWh

15.

Apparent power (S) is given by:

a)

$S=VI$

b)

$S=V+I$

c)

$S=\frac{V}{I}$

d)

$S=VI\sin\theta$

16.

The graphical relation of S, P and Q is represented using:

a)

Phasor diagram

b)

Power triangle

c)

Voltage triangle

d)

Current wave

17.

Power factor is defined as:

a)

$\tan \theta$

b)

$\sin \theta$

c)

$\cos \theta$

d)

$\theta=-1$

18.

For inductive loads, reactive power value is:

a)

Negative

b)

Zero

c)

Positive

d)

Infinity

19.

For a pure resistive load, reactive power Q is:

a)

−10

b)

Positive

c)

Zero

d)

Infinite

20.

A low power factor means:

a)

System uses power well

b)

There may be penalty charges

c)

Voltage equals current

d)

No reactive power

Chapter 2a

Total questions: 20

Worksheet time: 10mins

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