Question

What is (a) the highest, (b) the lowest total resistance that can be secured by combinations of four coils of resistance 4 Ω, 8 Ω. 12 Ω. 24 Ω?

Answer 1

12 and 24

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Answer 2

Answer:

We know, highest resistance is got when the resistances are connected in series connection.

Given R1 = 4 ohm, R2 = 8 ohm R3 = 12 ohm R4 = 48 ohm

Therefore resistance in series = R1 + R2 + R3 + R4 = 4 + 8 + 12 + 24 = 48 ohm

         

So, highest resistance = 48 ohm.  

b) The lowest resistance = resistances are connected in parallel

Total resistance in parallel, 1/R = 1/2 + 1/8 + 1/12 + 1/24 = 12/24

1/R = 1/2 ohm, R = 2 ohm

Therefore lowest resistance is 2 ohm.