Question

two resistors with resistance 5 ohm and 10 ohm are to be connected to a battery of 6v so as to obtain:
(i)minimum current
(ii)maximum current.
how will you connect the resistances in each case?

Answer 1

Given that, two resistors with resistance 5 ohm and 10 ohm are connected to a battery of 6V.

We have to find the minimum and maximum current.

Take R1 = 5 ohm and R2 = 10 ohm

(i) For minimum current, connect both the resistance in series.

For series combination:

-----------| R1 |-----------| R2 |------------

Rs = R1 + R2

Rs = (5 + 10) ohm

Rs = 15 ohm

From ohm's law we can say that,

V = IR

6 = I × 15

I = 6/15

I = 0.4 A

Therefore, the minimum current is 0.4 A.

(ii) For maximum current, connect both the resistance in parallel.

For parallel combination:

----------------| R1 |------------------

----------------| R2 |------------------

1/Rp = 1/R1 + 1/R2

1/Rp = 1/5 + 1/10

1/Rp = 1/5(1/1 + 1/2)

1/Rp = 1/5(3/2)

Rp = 10/3

Rp = 3.33 ohm

From ohm's law

V = IR

6 = I × 3.33

I = 6/3.33

I = 1.8 A

Therefore, the maximum current is 1.8 A.