Question

How can three resistors of resistances 2ohms, 3ohms & 15 ohms be connected to give a total resistance of :
a)16.2 ohms. b) 3.75 ohms. c) 4.5 ohms ?

Answer 1

Given:

2ohms, 3ohms & 15 ohms of resistors.

To find:

How can three resistors of resistances 2ohms, 3ohms & 15 ohms be connected to give a total resistance of :

a)16.2 ohms. b) 3.75 ohms. c) 4.5 ohms

Solution:

From given, we have 2ohms, 3ohms & 15 ohms of resistors.

There are 8 possible combinations in 4 cases.

Case I: All resistors connected in series

2 + 3 + 15 = 20

Case II: All resistors connected in parallel

1/2 + 1/3 + 1/15 = 0.9

Case III: 2 resistors connected in series and 1 in parallel

1/2 + 3 + 15 = 18.5

2 + 1/3 + 15 = 17.33

2 + 3 + 1/15 = 5.06

Case IV: 2 resistors connected in parallel and 1 in series

1/2 + 1/3 + 15 = 15.83

1/2 + 3 + 1/15 = 3.566

2 + 1/3 + 1/15 = 2.4

Therefore, none of the given options are right.