Please check my understanding.
If the wire that connects two ends of the battery is not ideal, R ≠ 0, then the current flows though load, 10Ω, will be constant and equal to 5A no matter how small/big R is provided that it is not zero.
If R = 0 then it is indeterminate, we don't know about the voltage across the load and its current.

 

If the wire that connects two ends of the battery is not ideal, R ≠ 0, then the current flows though load, 10Ω, will be constant and equal to 5A no matter how small/big R is provided that it is not zero.
If R = 0 then it is indeterminate, we don't know about the voltage across the load and its current.

Nearly.

We have all agreed this question is a 'trick' question since it is ill posed.

With real components you have to take into account contact (connection) resistance as R diminishes.

So the total load on the voltage source will be a combination of the strapwire and all connection resistances and the 10 ohm resistor.

The current through this lot will be 50/ whatever this resultant resistance is

up to the output capacity of the ideal source

It is so often forgotten that we can only apply any mathematics within stated limitations, in this case the cource is ideal upt to X amps.

A real source has an effective series output impedance which is in series with the load and provides a different (but still calculable) fall off of current.

It is practice to measure the and specify open and short circuit values for a source to determine these parameters and if they are within tolerance.

No one rushes off and worries over 0/0, we just improve our physical model to better reflect reality.

 

So, my answer above is correct if all contacts + voltage source are ideal?

 

Up to the capacity of the ideal source.

 

Sorry but I still don't get it. When you say about "capacity of ideal source" I think you mean about its maximum current because its internal resistance and therefore the maximum current it can supply will be E/internal resistance.
But I am assuming that the battery also ideal, meaning that its internal resistance is zero and the maximum current it can supply is infinity, right?

 

Keep in mind that any time you talk about an "ideal" anything, that you are not talking about a real thing. We are free to assign capabilities and restrictions that allow us to get more accurate answers to real problems of interest. We do this all the time with opamps -- for instant, we are always talking about "ideal opamps powered by ±15V supplies". By this we mean that we are ignoring all of the nonideal behavior except that it will saturate at +15V or -15V and not go any further.

We often impose a maximum current capability on an otherwise ideal voltage source or a maximum voltage capablity on an otherwise ideal current source, because many real world supplies behave close enough to that model for it to give use acceptably good results with a minimum of complexity.

 

Thanks, I just wanted to understand about " output capacity of the ideal source" in Studiot
post.
What is really confusing is the word "ideal" above. When we say about ideal source, do we talk about its capacity?
For example, with an ideal voltage source, the maximum current it can supply is infinity. Then current capacity of it is infinite. And it seems useless to mention it.

 

Thanks, I just wanted to understand about " output capacity of the ideal source" in Studiot
post.
What is really confusing is the word "ideal" above. When we say about ideal source, do we talk about its capacity?
For example, with an ideal voltage source, the maximum current it can supply is infinity. Then current capacity of it is infinite. And it seems useless to mention it.

Then, by all means, feel free to interpret the current capacity of the ideal source he was talking about to be infinite current and use that.

 

If the "ideal wire" really has 0 ohms, voltage on the wire can never exceed 0 for any value of current;

E=I*R,
=x*0 (E must be zero for any value of x, any value of current)

If you remember from the other thread I proved that in a load evaluation all cases can only be properly evaluated by having I on the right.

So even if the source can provide "infinity" current, the voltage across the wire is still zero, solving the question.

(Of course that only holds true for "infinity" current into an ideal wire, the original question was "50v" across an ideal wire which simply cannot exist.)