#17 - Increasing the electrical load carried on a

[Administrator]

Please post your questions below!

[Andro10]

I'm having a hard time making a distinction between answers C and E. Could you please help?

[kithly]

We don't know that the "maximum operating temperature" of a transmission line can ever be changed or influenced. Say the "maximum operating temperature" is 100. Two things that affect the temperature of the transmission line are: amount of electrical load, and wind speed/direction. When there's too much electrical load on the line, the temperature will exceed 100 degrees. When there's an average electrical load on the line, maybe the resting temperature is 85 degrees. While operating at this "average load", the temperature of 85 degrees can still be affected by strong & perpendicular winds. If it's a particularly windy day, maybe the line temperature is 75 degrees as opposed to a completely still & neutral day.

C) Says that the electrical load the line can carry WITHOUT reaching maximum increases when wind speed increases. Maybe the average electrical load is actually 50% of maximum capacity (because if we turn it up to 100% then the line temperature will pass 100 degrees temperature). Since wind speed decreases the "resting temperature" from 85 degrees to 75 degrees, we can lightly assume that the average load can be turned up - from 50% to at least 51%.

E) This says that the MAXIMUM OPERATING TEMPERATURE - the one we established to be 100 degrees - is changed by windy degrees. This is unsupported. Maximum operating temperature is just that - the maximum. It's like the limit that comes with the design of the product. You can't change the maximum temperature you can set your oven to, but you can change the temperature of your oven WITHIN that range.

[Andro10]

Hey Kithly, thank you so much for your explanation. It makes sense now.

[Jon Denning]

Kithly is spot on here! Electrical loads and wind speed/direction aren't said to affect the maximum operating temperature, which could be a fixed number at all times. Electrical loads and wind only affect the actual temperature, so (E) is a classic shell game trap: the maximum electrical load a given line can carry without exceeding the max temp is higher on windy days than on calm days (since the wind helps offset the temperature increase), but the maximum temp the line can stand may not change at all.

Answer choice (C) on the other hand fits with what we're told, in that you can run a greater load through a line when there's more wind to cool it off.

As for the other three wrong answers:

(A) we don't know the behavior of electrical companies based on this stimulus.

(B) we don't know the wind speeds in this answer choice, so even though right angle winds are more effective than parallel winds, without knowing the other key factor—prevailing wind speed in each case—we can't say that (B) is true.

(D) air temperature is never mentioned in the stimulus (only air movement), so (D) includes new information the effect of which cannot be known.

[cpihl13]

Just for my clarity, is this considered a Must be True/Most Supported question or a Strengthen/Support?

I feel that it is a MBT/Most Supported because it reads as "most strongly supported" but I wanted to make sure!

Thanks,

[Adam Tyson]

You're correct, Cole! The stimulus here is supporting the correct answer, not the other way around, so it's a "Most Strongly Supported question, which we treat as a subset of Must Be True. If it were a Strengthen question the stem would have to say something about the answers being accepted as true, like "which of the following, if true, would..."