EMF, Internal Resistance, and Terminal Voltage of Batteries Explained | Doc Physics
Some people call it a dry cell; I call it a sling blade. Mmmhmmm. We will figure out why my laptop and cell phone heat up when I use them a lot. Yay!
Video Rating: 4 / 5
Taken from the UCCP Introductory Physics course. © 2009 The Regents of the University of California This course is designed to acquaint you with topics in cl…
I love u and ur channel. You’re a great teacher!
Thanks man.
At 12:22 , you could have said I’m taking common denominators so that It’s
easy to understand. Great video BTW. :)
It would be much more helpful to the audience if you showed the working for
your calculations.
i love you man
I need your help. I did the math but my answers are: 6.6v (for circuit 1
wherein the total resistance is 2) 1.2v (for circuit 2 wherein the total
resistance is 11) 0.13( for circuit 3 wherein the total resistance is 101).
I think i did something wrong.Just can”t figure out what. I used the
formula V= I*R by first taking out the current across the circuit and
multiplying it with 1 which is the resistance of the resistor on my left.
Why is my method wrong?
Doc how am I supposed to calc the battery emf if given only current flowing
as 20mA
Does more voltage or more current make bulb brighter?
If you were struggling with the find the voltage part. Add the resistances
together, then divide the 13.2 V by that total resistance value. Then do
13.2 V subtract the value you got to get the voltage you are looking for
how can you get 6.6v,12v and 13.1 volt against Rinternal as you pointed
towards Rint and ask viewers to calculate voltage?Vx=Rx*Vt/Rt
Thank you so much for making this video sir. Helped me with physics 2 and
also entertaining. Subscribed
great video and explanations to everything! one personal opinion and you
may or may not agree is i dont like that formula you proposed at the very
end. because if I was to just look at that on a formula sheet, quite
frankly i would have no idea where that came from or how it was derived,
therefore i would not understand any theory behind it. with just getting
the same answer like i did in the first couple of minutes of the video i
actually remember it and it makes complete sense and makes me think. with
this formula its just plugging in numbers. regardless though, awesome job
and keep it up 10/10
how i wish you were my physics teacher
HOW DID YOU FIND THE VOLTAGE VALUES ???
Lol this made me laugh and then do the problem! Thanks!
How would you find the voltage drop?
Umm thank you :)
So the emf is the maximum potential difference between to electrodes?
Excuse my english, it’s not my native language
if 4 bulbs = 1.325 and 3bulbs= 1.325 how come the resistance is different
I don’t like that R_int. I think all our lives would be better if it were
zero. I do like puzzles though.
Suppose I have a box, and I paint it black. (This is essential, because
after we are done I want to seal the box and keep its contents secret: a
true ‘black box’.) The idea is that we put a battery in the box, and no
other sources of electrical energy. We can put in any electrical components
that we want. But no other electrical energy source! Just the battery. Can
we then get rid of R_int? We can put in transistors, opamps, IC’s of
whatever nature, capacitors, resistors, bulbs, coils, wires, enitire
voltage regulator chips, a computer, whatever. But no other electric energy
source (did I mention that?). Can we then do it? Can we eliminate R_int and
have the box produce a voltage, possibly a little less than the original
V_emf, that does not depend on the external load? Or is this impossible in
principle?
To get puzzlers going, imagine that we put in an entire current meter and a
small embedded computer, powered by the battery. Then when someone hooks up
an external load, the computer ‘sees’ the current go up, and might take
action to compensate for the voltage loss (by switching some transistors or
something). This is a straightforward exercise in voltage regulation, that
is done all the time in power supplies. When you begin to feel that this
might be possible, then realize the starkness of the question: the box is
an ideal voltage source, without R_int. Seriously? In reality? Electrons
travel through the box, they are pushed only so much. Whichever complicated
path they follow inside the box, there must surely be some resistance along
that path. No way this can work. Do you feel the two approaches fighting
inside your brain? Good. :-)
is it because of the number of bulbs
Two*
Excellent intro to basic physics, thank you :-)