Understanding Electric Current and Resistance

The video introduces the basics of electrical current and Ohm's Law. It explains the definition of electric current, its calculation, and the concept of drift velocity. The video also covers how current flows through circuits, the historical definition of current direction, and the application of Ohm's Law. Examples of current calculations and resistance in circuits are provided, along with a discussion on resistors and their color coding. The session concludes with a summary of the key points discussed.

What is the unit of electrical current?

• Volt

• Coulomb

• Ampere

• Ohm

How is electric current defined?

• Rate of charge flow

• Voltage across a wire

• Amount of charge

• Speed of electrons

If a truck battery sets in motion 720 Coulombs of charge in 4 seconds, what is the current?

• 72 amps

• 72 milliamps

• 180 amps

• 180 milliamps

How long does it take for 1 Coulomb of charge to flow through a calculator if the current is 0.300 milliamps?

• 3.33 seconds

• 3.33 minutes

• 3.33 x 10^3 seconds

• 3.33 hours

In which direction does the current flow in a circuit?

• From positive to negative

• From negative to positive

• It does not flow

• In random directions

What is the drift velocity of electrons in a wire?

• 10^-3 meters per second

• 10^3 meters per second

• 10^-4 meters per second

• 10^4 meters per second

According to Ohm's Law, what happens to the current if the voltage increases?

• It remains the same

• It becomes zero

• It decreases

• It increases

What is the relationship between current and resistance according to Ohm's Law?

• Directly proportional

• Inversely proportional

• No relationship

• Exponentially proportional

What is the unit of resistance?

• Volt

• Ohm

• Ampere

• Coulomb

What is the resistance of an automobile headlight through which 2.5 amps flows when 12 volts is applied?

• 6.8 ohms

• 7.8 ohms

• 5.8 ohms

• 4.8 ohms