Fundamentals of Circuits I: Current Models, Batteries & Bulbs

Fundamentals of Circuits I: Current Models, Batteries & Bulbs v 0.1
Question 1.3 Do the charges generated by rubbing and by the power supply cause different
effects If so, describe them. Do the charges generated in these two ways appear to
be different
The rate of flow of electric charge is more commonly called electric current. If charge ∆Q
flows through a conductor in time ∆t, then the current can be expressed mathematically
by the relationship
I = ∆Q
∆t .
The SI unit of current is called the ampere (A). One ampere represents the flow of one
coulomb of charge through a conductor in a time interval of one second. Another common
unit of current is the milli-ampere (mA). (1 ampere = 1000 milli-amperes). It is common
to refer to current as ”amps” or ”milliamps.”
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Figure 2: Moving Charges
Question 1.4 Consider Figs. 2(a) and 2(b). Do both figures show a current to the right
Explain.
Activity 1.2: Arrangements that Cause a Bulb to Light
In this activity, you can begin to explore electric current by lighting a bulb with a battery. You
will need the following:
• flashlight bulb (#14)
• flashlight battery (1.5 V D cell)
PHYS-204: Physics II Laboratory 4