Chapter 6.2

Question 1

What is the definition of resistance?

Answer 1

-it is the opposition within any material to the movement and flow of charge

Question 2

What are materials that offer almost no resistance and what are materials that offer very high resistance?

Answer 2

Very high resistance
->insulators

No resistance
->conductors

Question 3

What are the three properties that the resistance of a resistor is dependent upon?

Answer 3

-it is dependent upon cross-section area, length, temperature and resistivity

Question 4

How does resistivity affect resistance

Answer 4

• a conductor has lower resistivity than an insulator
• > higher resistivity= higher resistance

-resistivity is directly proportional to the resistance

Question 5

How does length affect resistance

Answer 5

• resistance is directly proportional to length

- >the longer a resistor, the larger the resistance

Question 6

How does cross sectional area affect resistance

Answer 6

• cross sectional area is inversely related to resistance
• > the larger the cross sectional area, the smaller the resistance
• the more cross sectional area, the more conduction pathway
• > resulting in more current that can flow
• > the wider the resistor, the less resistance to the current flow

Question 7

How does resistance relate to temperature?

Answer 7

• at higher temperatures, the resistance is greater for conductors
• > this is because of increased thermal oscillation of atoms in a conductive material
• > resulting in greater resistance to electron flow

Question 8

What is the Ohm’s law useful for?

Answer 8

-it basically states that for a given magnitude of resistance, the voltage drop across the resistor will be proportional to the magnitude of current

Question 9

What is internal resistance?

Answer 9

• conductive materials themselves may act as weak resistors

- >therefore, they may cause a drop in electric potential from the start

Question 10

What is the internal resistance if a cell is not driving any current

Answer 10

• the internal resistance is zero

- >and the voltage is equal to the emf

Question 11

How do second batteries work

Answer 11

• an external voltage is being applied

- >to drive the current towards the positive end of the secondary battery

Question 12

What does the cell acts as when it discharges vs when it recharges

Answer 12

• it acts as a galvanic(voltaic cell) when it discharges

- it acts as a electrolytic cell when it recharges

Question 13

What is power defined as?

Answer 13

• it is defined as the rate at which energy is transferred or transformed
• > or the rate at which energy is dissipated by a resistor

Question 14

What is the voltage drop like for a parallel pathway?

Answer 14

• there is no voltage drop
• > voltage remains constant for parallel pathways
• > no matter which path is taken, the voltage drop experienced by each current is the same