Electrical Power & Ohm's Law

When 20 coulombs of charge pass a given point in a conductor every 4.0 seconds, the current through this point is (Hint: current is the flow of charge per second)

• 80 A

• 0.20 A

• 16 A

• 5.0 A

An ampere can be defined as one

• coulomb per second

• joule per coulomb

• newton per coulomb

• ohm per volt

Tags

NGSS.HS-PS2-5

NGSS.HS-PS3-5

To decrease the electrical resistance of a metal conductor one should

• cool the conductor to a low temperature

• decrease its radius

• decrease its cross-sectional area

• increase its length

A copper wire has a resistance of 200 ohms. A second copper wire with twice the cross-sectional area and the same length will have a resistance of (Hint: resistance is inversely proportional to cross-sectional area)

• 50 ohms

• 100 ohms

• 200 ohms

• 400 ohms

How much current passes through a 12-ohm circuit operating at 3.0 volts? (Hint: think of Ohm's Law)

• 0.25 A

• 0.75 A

• 3.0 A

• 4.0 A

The ratio of the potential difference across a conductor to the current in the conductor is called (Hint: think of Ohm's Law)

• conductivity

• resistance

• charge

• power

The resistance of a 60 watt bulb operated at 120 volts is approximately (Hint: use an equation for Electrical Power)

• 720 ohms

• 240 ohms

• 120 ohms

• 60 ohms

A 1.5 volt battery is connected to a 10 ohm resistor. What current passes through the resistor? (Hint: think of Ohm's Law)

• 6.7 A

• 150 A

• 0.15 A

• 15 A

Calculate the energy usage of a 100 watt light bulb over the course of 2.0 hours (Hint: careful with your unit for time)

• 1.2 x 10⁴ J

• 200 J

• 6.0 x 10³ J

• 7.2 x 10⁵ J

Name this circuit element.

• battery

• fixed resistor

• lamp

• switch