Part 7 is included in the end Electricity. Introduction to the Digital Multimete
ID: 3279633 • Letter: P
Question
Part 7 is included in the end
Electricity. Introduction to the Digital Multimeter
How does the current (I) through the flashlight using the good batteries compare to the current through the flashlight using the bad batteries? The flashlight has manufacturer specifications of 3.0 V and 0.5 A. This means that 3.0 V and 0.5 A required to make the flashlight turn on brightly.
In the last part of step 7 of the procedure, you measured the resistance of the flashlight when it had no current passing through it. The resistance of the flashlight is different, however, when current is passing through it. Explain how you measurement of the resistance of the variable resistor obtained in part 7 is a valid approximation of the resistance of the flashlight when it had current passing through it. Is the resistance higher when the flashlight is on or off?
This is My measurement for Part 7: Measuring resistance of a light buld
Resistance of variable resistor: 3.3
Resistance of cold light bulb: 1.4
Explanation / Answer
a) When good batteries are used the current is more compared to when bad batteries are used.
b)
for measuring a resistance a small current is passed through the resistor and the voltage across the resistor is measure. In the case of
The internal resistance of the multimeter is very high compared to what we are measuring and hence the small current passing through the flas bulb will have very little impact on the measurement. Hence the mesurmenet is a good approximation
when current passes through the flash bulb the filament is heated and resistance increases with temperature. Hence resistance is more when when the bulb is on.