how will you connect three resistors of resistances 2ohm,3ohm and 6ohm to obtain a total resistance of:(a)4ohm (b)ohm

Asked by snigdhaa138_461 | 11th Sep, 2010, 08:44: PM

Expert Answer:

While attempting such questions, you have to keep in mind that:
1. In series, the resultant resistance is greater than the largest resistance put in the series.
2. In parallel, the resultant resistance is lesser than the smallest resistance put in parallel.
 
Now, see what is the desired net resistance.
 
(a) u want 4 ohm. To get this you cannot have 6 in series (6 > 4. is you use 6 in series, resultant will be even greater than 6. we want only 4)
 
 
 
Now start hit and trial. first put all in parallel. gives 1 ohms. too low. so put 3 and 6 in parallel, 2 in series with the resultant of 3 and 6. this gives the desired resistance.
 
(b) Zero ohms is not possible. Whatever combination you use, you will get some resistance as you are putting some resistance in the circuit.
 

Answered by  | 11th Sep, 2010, 10:35: PM

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