Chapter 17: Direct current

Which statement is FALSE about electricity?

• Electric current is defined as the rate of charge flow

• The resistance will increase when the temperature increase

• The electric current decreases when the resistance increases

• The resistivity increases when the length of the conductor increases

If the resistor are connected in parallel in a circuit which one has the highest current?

 $R_1\ <\ R_{2\ }<\ R_3\ <\ R_4\$  

•  $R_1$  
  

•  $R_2$  

•  $R_3$  

•  $R_4$  

Which of the following parameter DOES NOT alter the electrical resistance of a piece of metal wire?

• The temperature of the wire

• The diameter of the wire

• The type of material of the wire

• The direction of the current flow in the wire

If the length of the wire is doubled and its area of cross section is decreased to half, then its resistance

• Increased by 4 times

• Increased by 2 times

• will become half of its initial value

• Remains the same

A battery is connected across a parallel combination of 2 identical resistor. If the potential difference across the terminals is V and the current in the battery is I, Then:

• The potential difference across each resistor is V and the current in each resistor is I

• The potential difference across each resistor is V/2 and the current in each resistor is I/2

• The potential difference across each resistor is V and the current in each resistor is 1/2

• The potential difference across each resistor is V/2 and the current in each resistor is I

What is current measured in?

• Ω (Ohms)
• V (Volts)
• A (Amps)
• W (Watts)

What is resistance measured in?

• Ω (Ohms)
• V (Volts)
• A (Amps)
• W (Watts)

What is Resistance?

• The flow of electrons
• Electric potential difference
• A battery
• The ability to reduce the flow of electrons

The mathematical relationship among Voltage, Current, and Resistance

• Faraday's Law
• Tesla's Law
• Edison's Law
• Ohm's Law

Current times Resistance equals
 (I X R)

• Power
• Voltage
• Amperage
• Ohm