AC Theory Lesson 7

? is the opposition to AC current flow caused by a capacitor.

a.

Capacitance

b.

Capacitive reactance

c.

Impedance

d.

Reactance

The unit of measure for capacitive reactance is the ? .

a.

farad

b.

henry

c.

hertz

d.

ohm

? is the opposition offered to the flow of current by the reaction of a capacitor.

a.

Capacitance

b.

Capacitive reactance

c.

Impedance

d.

Reactance

? is the abbreviation for capacitive reactance.

a.

C

b.

X

c.

X

d.

Z

Drag the terms below to the appropriate locations to create the formula to find capacitive reactance. Be sure to place the variable of the item you are solving for on the

left.

When using the formula for calculating capacitive reactance, the frequency must be

expressed in hertz and the capacitance in ? .

a.

amps

b.

farads

c.

henries

d.

ohms

400 kilohertz = ? hertz

30 microfarads = ? farads.

200 picofarads = ? farads

Select the correct option to complete the following sentences.

If the capacitance of a capacitive circuit is ? , the capacitive

reactance is increased.

If the frequency of a capacitive circuit is ? , the capacitive reactance is decreased.

Possible answers

increased

decreased

A 200 µF capacitor is connected to a 60-hertz source. What is its capacitive reactance?

(Round the FINAL answer to one decimal place.)

How much current flows in a 240-volt, 400-hertz circuit that is connected to a 50-

microfarad capacitor? (Round the FINAL answer to the nearest whole number.)

What is the capacitive reactance of a 200-picofarad capacitor when connected to a 700-

kilohertz, 500-volt source? (Round the FINAL answer to the nearest whole number.)

Solve for the capacitive reactance and the capacitance in the circuit shown. (Round the

FINAL answers to at least two decimal places in the specified unit.)

X = ? Ω

C = ? µF

Solve for the capacitive reactance and the total current in the circuit shown. (Round the

FINAL answers to at least two decimal places in the specified unit.)

X = ? Ω

I = ? A

Solve for the capacitive reactance and the capacitance in the circuit shown. (Round the

FINAL answers to at least two decimal places in the specified unit.)

X = ? Ω

C = ? µF

In this circuit, It = 0.05 A, C = 0.5 µF, and Xc = 100Ω. Solve for Es

Answer:

In this circuit, It = 0.05 A, C = 0.5 µF, and Xc = 100Ω. Solve for f. (Round the FINAL answer to the nearest whole number.)

Answer:

Hz

The capacitive reactance of a 240-volt, 60-hertz circuit is 30 ohms. What is the current

flow?

Answer:

Solve for the capacitive reactance and the total current in the circuit shown if the

frequency is 200 hertz. Then calculate the values again at 60 hertz. (Round the FINAL

answers to at least two decimal places in the specified unit.)

Xc@200hz = ? Ω

It@200hz = ? mA

Xc@60hz = ? Ω

It@60hz = ? mA

Current flows through a capacitor because of the increase and decrease of voltage and change in the direction of current.

Select one:

True

False

In a charged capacitor, the voltage across the plates of the capacitor opposes the applied voltage.

Select one:

True

False

In reality, in a capacitive AC circuit, current only flows back and forth as a result of the increase and decrease in voltage and the change in ? .

a.

capacitive reactance

b.

current

c.

frequency

d.

polarity

The current flow in a pure capacitive circuit leads the applied voltage by ? .

a.

60°

b.

90°

c.

120°

d.

270°

Select the correct option to complete the following sentences.

If the frequency of a capacitive circuit ? , the current is

increased.

If the voltage of a capacitive circuit ? , the current is

increased.

possible answers

is increased

is decreased

Current through a capacitive circuit is ? proportional to the frequency and ?

proportional to the voltage.

a.

directly / directly

b.

directly / inversely

c.

inversely / directly

d.

inversely / inversely