A battery is connected to the endpoints A and B of a homogeneous wire. Using an ammeter one finds that a current I = 1 . 5 A flows through the conductor. Then, the wire is bent in the form of a circle and the same battery is connected to points A and B. What is the current in Amps flowing through point C in this case? You may neglect the internal resistance of the battery.
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the circle is connected as two parallel resistances !! shouldn't the current through c be 1.5 as well!!
That's what I thought as well. Even my science teacher said 1.5A :P
my first answer was 1.5 but i got it right eventually
I think most of you who are getting 1.5 amps as an answer are forgetting a vital formula that was essential in solving this problem. There is a relationship between length of wire and resistance. This factor will change 1.5 amps into 3 amps. The formula is R= (P * L)/A. P is resistance of the wire, L is the length of the wire, and A is the perpendicular-cross sectional area of the wire.
if it takes shape into circle then why it's resitance no change as R is proportional to L
Read allaboutcircuits.com
A battery is connected to the Point A and Point B of a homogenous wire. Therefore, both flow together and it is bent into a circle shape so both of the wires are at the same length. Then find Point C I = 1.5A Amps of Point C = Point A + Point B Amps of Point C = 1.5 + 1.5 = 3 Amps
No it has only 1 wire but both have same length
Don't forget to mention about using ohms law.
This one is extremely simple.
Alright so we know I = R V (ohm's law), and the internal resistance of the wire can be given as R = * A p × L , where * V is the voltage, I is the current, R is the resistance, L is the length of the conducting wire, p is the resistivity of the conducting wire, and A is the perpendicular-cross sectional area of the wire (imagine the wire being a long cylinder, and A being the area of the base circle).
From these, we can plug in the resistance formula and achieve this...
*I ∝ * L 1
which is a bit counter-intuitive, but hey, you've probably already been warned about this.
This means that if the length of wire from one battery to another is shortened by a factor of 2 1 , the current running through will raise by a factor of 2 .
This gives us our answer, 2 × 1 . 5 A m p s = 3 . 0 A m p s
This answer, of course, is assuming that the bottom half of the circle has become a separate circuit from the top half.
Let the resistance of the wire be R . The first thing to remember is that the resistance is directly proportional to the length of the wire . So, in the second case, as the semicircular piece of the wire between A and B is exactly half the length of the original wire, the resistance of each piece will be 2 R . As the two pieces of the wires are connected in parallel, the voltage across the terminals will be the same, say V . So, by Ohm's Law, V = I ′ 2 R = I R . Since the resistance is halved, the current is doubled so that V remains the same. Therefore, I ′ = 2 I = 3 A
Correct solution good work!!
Its current in parallel.
current flows equally from both sides.
and let the current flowing from c is x
1/AB = 1/x + 1/x
1/1.5 = 2/x
x = 2 x 1.5
x=3
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Assume the wire's resistance is 2 ohms. Then the voltage of AB is 3 volts by ohm's law which is V = IR. When the same wire is bent into a circle, the distance of AB is half of the length it used to be therefore the resistance also halfs. Now each branch is 1 ohm and the voltage drop across each branch is still 3 volts by using the voltage divider formula. Subsistuting these values in the ohms law equation, we solve for I = current. 3= Current * 1. Now its simple to deduce that current flowing across point C is 3 amps.