Simple equivalent resistance question

AI Thread Summary
To achieve an effective resistance of 1.5Ω using 2Ω resistors, a minimum of four resistors is required, specifically three in series with one in parallel. The discussion emphasizes the importance of understanding combinations of resistors in series and parallel to solve such problems efficiently. It suggests starting with basic combinations and gradually increasing complexity to build familiarity. Creating a table of combinations up to seven resistors is recommended for practice. Mastery of these concepts will enhance problem-solving speed for similar objective-type questions.
shivam01anand
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Homework Statement



how many minimum no of resistances of eash 2Ω resistance can be connected to have an effective resistance of 1.5Ω

Homework Equations





The Attempt at a Solution



I tried to put 2 in parallel,series and different combinations.


After 5-10 mins of relentless trying i could not figure the answer[ I know it now ans=4 ( 3 in series with one in parallel)


My point being how to really get hold of this "type" of problem very quickly(objective type q).

and if its not too much could you point out some more similar questions to this on the internet for a grasp on this "Type" of question?

Thanks
 
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hi shivam01anand! :smile:
shivam01anand said:
My point being how to really get hold of this "type" of problem very quickly(objective type q).

you're looking for a factor of 3/4

you only get fractions from parallel, so start with 2 parallel to 1 (doesn't work), then 3 parallel to 1 (does work, in this case), then 4 parallel to 1, then 3 parallel to 2, and so on …

in fact, why not write out a table of all combinations now, up to say 7, to give you practice and to see how it works? :wink:​
 

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