Alternating current

All of the following have the same units except:

• inductance.

• capacitive reactance.

• impedance.

• resistance.

A resistor is connected to an AC power supply. On this circuit, the current

• leads the voltage by 90°.

• lags the voltage by 90°.

• is in phase with the voltage.

• none of the given answers

A pure inductor is connected to an AC power supply. In this circuit, the current

• leads the voltage by 90°.

• lags the voltage by 90°.

• is in phase with the voltage.

• none of the given answers.

If the frequency of the AC voltage across an inductor is doubled, the inductive reactance of that inductor

• increases to 4 times its original value.

• increases to twice its original value.

• decreases to one-half its original value.

• decreases to one-fourth its original value.

Quantity of charge can be measured in

• time (s)

• Ampere (A)

• coulombs (C)

• Joule (J)

The function of a generator is to change ____. 

• mechanical energy to electrical energy
• electrical energy to mechanical energy 
• electrical energy to chemical energy
• chemical energy to electrical energy 

Tags

NGSS.HS-PS3-3

NGSS.HS-PS3-5

The formula for inductive reactance is

• $\frac{1}{\omega L}$

• $\omega C$

• $\frac{1}{\omega C}$

• $\omega L$

A Capacitor blocks

• Only a.c.

• Only d.c.

• Both ac and dc

• None of these

The instantaneous current in an ac circuit is i=2.0 sin314t, what is its frequency?

• 100 Hz

• 60 Hz

• 50 Hz

• 2π

The instantaneous current in an ac circuit is i=2.0 sin314t, what is rms value of the current.

• 1.414 A

• 2.828A

• 1 A

• 2 A