Explanation:
As the given data is as follows.
[tex]R_{1} = 680 \ohm[/tex] ohm[tex]\ohm[/tex], [tex]R_{2} = 720 \ohm[/tex] ohm,
[tex]R_{3} = 1.2 k\ohm[/tex] = 1200 [tex]\ohm[/tex] (as 1 k ohm = 1000 m)
(a) We will calculate the maximum resistance by combining the given resistances as follows.
Max. Resistance = [tex]R_{1} + R_{2} + R_{3}[/tex]
= [tex](680 + 720 + 1200) \ohm[/tex] ohm
= 2600 ohm
or, = 2.6 [tex]k\ohm[/tex] ohm
Therefore, the maximum resistance you can obtain by combining these is 2.6 [tex]k\ohm[/tex] ohm.
(b) Now, the minimum resistance is calculated as follows.
Min. Resistance = [tex]\frac{1}{R_{1}} + \frac{1}{R_{2}} + \frac{1}{R_{3}}[/tex]
= [tex]\frac{1}{680} + \frac{1}{720} + \frac{1}{1200}[/tex]
= [tex]3.683 \times 10^{-3}[/tex] ohm
Hence, we can conclude that minimum resistance you can obtain by combining these is [tex]3.683 \times 10^{-3}[/tex] ohm.
