ࡱ> EGDq` !bjbjqPqP 5$:: 8 $X,88888&&&+++++++$B-h/+9r' &r'r'+88,8)8)8)r'^88+8)r'+8)8)c++8, G'{++(,0X,+00d(v00+00+(&'8)' 'S&&&++(^&&&X,r'r'r'r'  Physics Lab: Ohm's Law Name: ________________________ I. Objective: By the end of this lab I will experimentally derive Ohm's Law. II. Procedure: A. Connect the circuit as instructed by your teacher. Be sure that there is always a resistance and that the circuit is not shorted.   Ammeter Voltmeter Power supply The next instruction includes how to set up the meters. Be sure that you have wired the circuit as described then have your teacher check your work before turning on the power supply. B. Choose three resistors. R1 = _________ &! R2 = __________ &! R3 = __________ &!. Connect one of the resistors to the power supply. Turn on the voltmeter and adjust it to read DCV 20. Connect it in parallel (across) the resistor. Turn on the ammeter and adjust it to read 10 A. Place it in series with the resistor. Do not turn on the power supply. Have your teacher check your work now. Turn the dial on the power supply until the voltmeter reads 0.5V. Read the current from the ammeter. C. In the next section of this lab you will find a table for voltages from 0v to 10v in increments of 0.5v. Repeat the procedure above and read the current for voltages from 0.5v to the appropriate maximum voltage for your resistors. Should (0,0) be part of your table? Include it if you said yes. III Results: Tables and Graphs  V 0.0 0.5 1.0 1.5 2.0 2.5 3.0 3.5 4.0 4.5 5.0 5.5 6.0 6.5 7.0 7.5 8.0 8.5 9.0 9.5 10v IV. Analysis: For each resistor, plot a graph of Current (I) vs. Potential Difference (V). Print a copy of each graph for each member of the group. On the graphs develop a formula that relates I to V. Include the units for the constant. Compare the constant for your formula to the resistance used. Is the constant on the correct side? Explain. Is this true for all three graphs? Calculate percent error for each resistor. Write a general equation (replace the numerical resistance with the variable "R") that relates V, I, and R. V. Application to the Robot: A. Reduce the voltage to zero and replace the resistor with one of the robot motors. Increase the voltage and record the voltage across the motor and the current through the motor. There is a fourth column in the data table for your use. Obtain data points. Do not go over 10 volts! B. Create a graph of Current u~ V X [ ] t t  @I|}LTVu Z ] ! !v!!!!!!!!!!!켷켬켬좞h jh UUh%V hq5>* hq5hq&jhqOJPJQJUmHnHuhq5>*OJPJQJhq>*OJPJQJhqOJPJQJh1; OJPJQJ8pqW X \ ] u  |}1$7$8$H$^`  !1$7$8$H$1$7$8$H$!!>?@ABCDEFGHVW9: h1$7$8$H$^h & F1$7$8$H$1$7$8$H$^`- Av8Tp2 N , Pl. "$R&(1$7$8$H$^  !1$7$8$H$1$7$8$H$:lmnopqZ [ \ ]  ^`1$7$8$H$ & F1$7$8$H$(I) vs. Voltage(V). Describe any difference between this graph and the other two graphs. C. Make a hypothesis as to the reason for your statement above. Power (Watts) is the rate of energy delivered to the motor, i.e. the amount of energy per unit time [ J/s ]. If a Volt is a Joule per Coulomb and an Amp is a Coulomb per second, what is the formula for Power? Calculate the power output at the minimum and maximum voltage of your motor.     v!w!x!y!z!{!!!!!!!!!!!! & F1$7$8$H$ h1$7$8$H$^h & F1$7$8$H$30P/ =!"#$% H@H Normal CJOJPJQJ_HmH sH tH DAD Default Paragraph FontViV  Table Normal :V 44 la (k(No List 4@4 Header  !4 @4 Footer  !dC@d Body Text Indent1$7$8$H$^` OJPJQJhR@"h Body Text Indent 2@(1$7$8$H$^@`( OJPJQJ $pqWX\]u|}>?@ABCDEFGHVW9:lmnopq & ' ( ) i j k l m n B C D E F G 0000000000000000000000000000000000000000 00 00000000 00000000000000000000 000000 0I00I00I00I00I00I00I00I00I00 ! : ! ! 8?A@T5@( ,4 <   # H2   C   B2   3  <   # N*[N  S Zff H  C Z  N  S Z33 NB  S DHB  C DHB  C D HB  C D<  # 0HB  C D,HB  C D/HB  C D.HB  C D-HB  C D*HB  C D2HB  C DHB  C DHB   C D HB ! C DHB " C D"HB # C D%HB $ C D$HB % C D&HB & C D'HB ' C D(HB ( C D1HB ) C D+HB * C D)HB + C DHB , C D3HB - C DHB . C D!HB / C D#HB 0 C DNB 1 S D HB 2 C DHB 3 C DHB 4 C D< 5 # B2 6 3  H2 7 C  6 8  6r 9   < : # 6 ;  6r <  H2 = C  B2 ? 3  HB @ C DB S  ?XYZ]^_`abcdefghijklmnopqrs : C3t< H t;6 l t@ t? lt=' m t ] t7g:t5dtt y` t9C `t1xt+rttt |-9t6gCt4xt3mtMt$ t M` t2mmt  t8at0 = t+''= t4"5"= t-h h = t= t!= t = t.= t"01) t/dd) t$= t#= t%= t& = t' = t*= t= t)= t)tq)rt)t ) t )= t() t($)$= t,&&= tώu z 9*urn:schemas-microsoft-com:office:smarttagsplace 4 o >rt   33333  adVzv^`o(.^`.pLp^p`L.@ @ ^@ `.^`.L^`L.^`.^`.PLP^P`L.adV1; q%V @24 @@@ @@@@@UnknownGz Times New Roman5Symbol3& z Arial3z Times h嚁&$& H  xxd 2qHX?%V2Lab: " Ohm's Law " Chuck Gehrman Administrator Oh+'0   @ L X dpxLab: " Ohm's Law "Chuck Gehrman Normal.dotAdministrator9Microsoft Office Word@ @{@~@Z/ ՜.+,0 hp  山ּCollege in Maryland  Lab: " Ohm's Law " Title  !"#$%&'()*+,-./012356789:;=>?@ABCFRoot Entry FNGHData 1Table@0WordDocument5$SummaryInformation(4DocumentSummaryInformation8<CompObjq  FMicrosoft Office Word Document MSWordDocWord.Document.89q