Physics 132DC Circuits and Ohm's Law Lab Report Questions (12 Points) 1. State the equation for Ohm’s law. What do the variables V, I, and R stand for, and what are theunits of each? Of the units listed, which one is equivalent to coulomb/second? (1 point) 2. From Part 3.1.1 ( Voltage Source): Produce a graph of output voltage Vout as a function of thesliding contact position x, measured from the bottom end of the slide wire resistor. Verify thatthe data points fall on a straight line rather than a curve ( don’t actually compute the slope). Didthe current change while you varied the sliding contact position x ? ( Hint: Your current meterwas switched off during this part, but this question can be answered using Ohm’s law and yourgraph.) (2 points) 3. From part 3.1.2 ( Ohm’s law ): Produce a graph of voltage V as a function of current I. Computethe slope, which will give the resistance R ( in ohms) of the resistor. In the lab, you should alsohave deduced R from the color-coding on the side of the resistor itself ( recall in-lab question 1).Does your value for R fall within the manufacturer's expectations? (1.5 points) 4. From part 3.1.5 (resistors in series/parallel): Using color code, write the value of each resistorused in this part of the experiment (recall in-lab question 1). From this, compute the totalresistanceRtot(i) resistors in series, and (ii) resistors in parallel. You will need to use thefollowing two equations for computing total resistance: (2 points)Rseries=R1+ R21Rparallel=1R1+1R25. From part 3.1.5 (resistors in series/parallel): Use the measured voltage V and current I for thetwo cases:Rtot to calculate (i) resistors in series, and (ii) resistors in parallel. Compare yourmeasured values for the series and parallel cases to those calculated in the previous question.That is, compute the percent difference for each case. (2 points)6. An Ohmic device is one that obeys Ohm’s Law. According to your data, are carbon resistorsOhmic devices? Support your answer with references to your graphs and/or equations. (1 point) 7. From part 3.1.4 (Light Bulb): In reality a light bulb is not an ideal resistor. As the light bulbheats up its resistance increases. Pretend you measured the current through a light bulb atdifferent voltages and arrived at this data: Voltage (V) 0.5 1.0 1.5 2.0 2.5 3.0Current (mA) 9.76 18.18 24.59 28.15 31.05 31.86Plot a voltage as a function of current for this data. Please connect the dots instead of adding abest fit line. What can you say about the resistance of the light bulb? (1.5 points)8. When a typical circuit is switched on, the net displacement of electrons along a wire is about 1mm per second. If electrons have such a low net speed, why do lights and devices appear towork instantaneously when switched on? (1
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