Today at the beginning of class we were originally supposed to turn in lab section 4 and homework section 4. the due date was pushed back until tomorrow so that we would be able to prepare ourselves for tomorrow's quiz over lab 3, lab 4, and today's class notes. the class was then reminded that windmills are due on Friday. today's notes were over ohm's law and equivalent resistance.
ohm's law is V=iR where V is the battery voltage, i is the current, and R is resistance.
the equivalent resistance of a series network is the sum of each resistor or Req=R1+R2+R3...
the equivalent resistance of a parallel network is the reciprocal of the sum of the reciprocal of each resistor or (1/R)=(1/R1)+(1/R2)+(1/R3)...
for each of these concepts we completed some of the example problems.
in the middle of the notes Jacob mentioned never wanting to talk about parallels again and the next slide was about the equivalent resistance of parallel networks.
at the end of class, we were given about ten minutes to work on our homework which was an electric circuits worksheet that is due tomorrow.
QOD: Use the mathematical equations for finding equivalent resistance to explain the results you observed for bulb brightness in the lab.
R=R1+R2+R3... can be used to explain bulb brightness because the resistance from each light bulb in a series adds up to a total resistance. when that total resistance was higher the current was decreased. in the equation V=iR, if voltage is kept the same and resistance increases, the current must decrease.
1/R=1/R1+1/R2+1/R3... can be used to explain bulb brightness in the same way except that parallels decrease resistance and therefore increase the current if the battery voltage is kept constant.
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