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 bulb

Resistance of variable resistor: 0.80

Resistance of cold light bulb: 0.63

Answer 1

resistance usually increases with temperature, and so the bulb has a lower resistance when it is first switched on and will draw considerably more current during its brief warm-up period.

so, if we see the ohms law

V= IR

the voltage is directly proportional to resistance.

In your experiment, the variable resistor is a valid approximation as the flashlight when glowing will have a higher resistance than when it is off. in both situations measure the current, the higher the resistance the lower is the current passing through the resistor.