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P2: Quiz 5 – Answers
P2: Quiz 5 – Answers
1)
a)
i) Stays the same (constant)
ii) Wires and (fixed) resistors
b)
i) Any straight line on the graph that passes through the origin. An example is shown below
a)
i) Stays the same (constant)
ii) Wires and (fixed) resistors
b)
i) Any straight line on the graph that passes through the origin. An example is shown below
ii) For ohmic conductors at a constant temperature, the potential difference and current are directly proportional to each other. We can see this from the graph because the line passes through the origin and is linear (straight)
2)
a)
2)
a)
b) A greater current passing through a filament bulb causes the temperature of the filament bulb to increase, which increases the resistance of the filament bulb. This means that less current can flow through the filament bulb per unit of potential difference. This is why the I-V graph for a filament bulb starts to curve at higher currents.
3)
a)
3)
a)
b) No – a current can only pass through a diode in one direction.
c)
c)
4)
a)
4)
a)
b) The student completes the experiment by altering the resistance of the variable resistor. This alters the current travelling around the circuit. We vary the resistance of the variable resistor quite a few times and take readings for the current from the ammeter and potential difference from the voltmeter. We should repeat our experiment and find the average potential difference for each current.
We then swap over the wires on the power source (cell or battery) so that the current travels the opposite way around the circuit. We do the same process; vary the resistance on the variable resistor and take readings for current and potential difference, and then take an average.
The student will then have all of the values that they need to draw an I-V characteristic graph for a filament bulb.
5)
a) 4 Ω
b) 0.4 Ω
c) Lower
The steeper the line is for an ohmic conductor, the LOWER the resistance is for the ohmic conductor.
d) A flatter line like the green one that is shown below; the line needs to be flatter than both the red and purple lines.
We then swap over the wires on the power source (cell or battery) so that the current travels the opposite way around the circuit. We do the same process; vary the resistance on the variable resistor and take readings for current and potential difference, and then take an average.
The student will then have all of the values that they need to draw an I-V characteristic graph for a filament bulb.
5)
a) 4 Ω
b) 0.4 Ω
c) Lower
The steeper the line is for an ohmic conductor, the LOWER the resistance is for the ohmic conductor.
d) A flatter line like the green one that is shown below; the line needs to be flatter than both the red and purple lines.
Questions
Click here for a printable PDF of the graphs in this quiz.
1)
a)
i) At a constant temperature, does the resistance of an ohmic conductor increase, decrease or stay the same?
ii) Give 2 examples of ohmic conductors.
b)
i) Draw the I-V characteristic graph for an ohmic conductor at a constant temperature on the graph below.
Click here for a printable PDF of the graphs in this quiz.
1)
a)
i) At a constant temperature, does the resistance of an ohmic conductor increase, decrease or stay the same?
ii) Give 2 examples of ohmic conductors.
b)
i) Draw the I-V characteristic graph for an ohmic conductor at a constant temperature on the graph below.
ii) Describe the relationship between the potential difference and current for an ohmic conductor at a constant temperature. Explain your answer.
2)
a) Draw the I-V characteristic graph for a filament bulb on the graph below.
2)
a) Draw the I-V characteristic graph for a filament bulb on the graph below.
b) Explain why the I-V graph for a filament bulb has the shape that it has.
3)
a) Draw the symbol for a diode.
b) Can a current pass through a diode in both directions?
c) Draw the I-V characteristic graph for a diode on the graph below.
3)
a) Draw the symbol for a diode.
b) Can a current pass through a diode in both directions?
c) Draw the I-V characteristic graph for a diode on the graph below.
4) A student is going to undertake an experiment so that they can draw an I-V characteristic graph for a filament bulb. They use a battery, variable resistor, ammeter, voltmeter, filament bulb and some connecting wires.
a) Draw the circuit that the student can use to obtain the values for an I-V graph for a filament bulb.
b) Outline a method that the student can use to obtain the values in order to be able to draw an I-V graph for a filament bulb.
5) The graph below shows the I-V characteristics for two different ohmic conductors.
a) Find the resistance of ohmic conductor 1 (you can use any values on the line for ohmic conductor 1, but if you are unsure, use a potential difference of 2).
b) Find the resistance of ohmic conductor 2.
c) Fill in the gap in the sentence below with either “greater” or “lower”.
The steeper the line is for an ohmic conductor, the _________ the resistance is for the ohmic conductor.
d) On the above graph, draw a line for an ohmic conductor that has a greater resistance than both of the ohmic conductors (1 & 2).
b) Find the resistance of ohmic conductor 2.
c) Fill in the gap in the sentence below with either “greater” or “lower”.
The steeper the line is for an ohmic conductor, the _________ the resistance is for the ohmic conductor.
d) On the above graph, draw a line for an ohmic conductor that has a greater resistance than both of the ohmic conductors (1 & 2).