A certain voltage divider consists of three 1 k resistors in series. Which of the following load resistors will have the least effect on the output voltage?

ANS:A - 1 M

The formula for output voltage is;

V (out) = V (In) [ (RL / (R1 + RL) ]

So, if we take 1M ohm then the result will be V (out) = V (In) (0.9).
And if we take 1k ohm then the result will be V (out) = V (In) (0.25).
So, the output voltage will be less affected if the resistance value will be more so the correct answer is 1M ohm.