what will be the voltage accross it ?

[sagar474]

**broken link removed**

 

[Tahmid]

V = (7 + 4) / 2 = 11v/2 = 5.5v

 

[sagar474]

those are not resisters

 

[Tahmid]

yea, i know, those are two voltage sources, right?

 

[karesz]

And you dont know what their internal resistance is...

 

[AdvaRes]

You can't do that with two sources !
The voltage difference will results in a high current.
If the wire's resistance used to connect the two source is very small the current flowing from one source to another will be very big resulting in the fusion of the wire or the burning of the source that do not support it.

If the wire used have a big resistance. Suppose L is it's lenth and that you wanna know the voltage at the location x (from the 4V source). The situation is like if you have a voltage divider. The output voltage that you'll mesure will be (3x/L)+4 Volt.

 

[sagar474]

asume that the internel resistence is zero

 

[wpchan05]

asume that the internel resistence is zero

you are violating Kirchhoff's Voltage Law.

 

[AdvaRes]

asume that the internel resistence is zero

You'll see smoke and smell something bad
The result can be 7 or 4 or 0 Volt.

 

[karesz]

Dear sagar474,

"asume that the internel resistence is zero"
You can do it, but the electrons dont know it so(...
Internal resistance is never =zero!

greatings!
K.

 

[hameeds01]

asume that the internel resistence is zero

kool it means u r using a Batteries of 10,0000000...... Amp nice

to solve this problem u must know about the internal resistors, if the internal resistances are unknown then u can make a rough guess that the voltage would be in between 4 & 7,

 

[praveensss]

I = (V1 - V2) / R, R = 0, Thus I = Infinity, The current would rise till the wire melts and they both will exist as 7 and 4 V!
In a real case. the current would flow from the 7V source to the 4V source and the weaker of the 2 would burn out or the wire would give way. Always connect a small resistance in series with even equal sources connected in parallel!