Essay physics lab ohms law

832 Words May 10th, 2014 4 Pages
New York City College of Technology

Ohm’s law & resistors in parallel & in series

Lab 4
Class: PHY 1434-E475
Due date: March, 13 20144
Group Names: Hisham Sageer

Objectives:
Our object is to confirm Ohm’s law by analyzing the dependence of the electrical current as a function of voltage and as a function of resistance. Also, we studied the current flow and voltage in series and parallel. Finally, the lab determined the equivalence resistance of series and parallel combination of resistors and compared the results with theoretical data.

Theoretical Background:
The first thing that needs to be described in this lab is what the electric current I:
I =. The electric current is defined as charge
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Set the ammeter to the range of mA and the voltmeter across the resistor the range of 25V. b After the instructor has checked the circuits, turn on the power supply. c Vary the output voltage of the power supply from 4 V to 10 V in the increment of 1 V and record the readings of the voltage V across the resistor and the corresponding current I through the resistor in Table 1. d Using the same circuit setup, set resistance of the variable resistor box to R = 1200Ω and repeat the steps 2 and 3.
2 Investigate the variation of the current with resistance when the voltage is constant. a Use the same circuit setup and set the output voltage of power supply to 12V. b By keeping the output voltage of the power supply constant, vary the resistance of the resistor box from 700 Ω to 1700 Ω in increments of 200 Ω. Record values of the current I through the resistor and the corresponding resistance R in table2.

Data:
Attached to report.

Calculations:

1 Use the data from table 1 to plot a graph of current Vs. voltage for both values of the resistance. Determine the slope of the graph. From the slope of the graph find the resistance using:
a) R = R = R =1000 Ω
% diff = = 0%

b) R = R = R =1250 Ω

c) Slope = 12.7
V = 12 v

Questions:

1. Does your resistance follow Ohm’s law? Base your answer on your
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