physics question????

Question

A circuit with a 100 ohm resistor, followed by a parallel wiring with two 100 ohm resistors. What happens to the potential difference along a parallel resistor if the other one is removed.

Answer 1

It goes up.  Do it by example.

Assume a voltage of 100 V

The two parallel resistors of 100 ohm each gives a total resistanc of

Rtot = r1r2/(r1+r2) = 50 ohms

Since the voltage will drop proportionally across the two items in series,

There will be a 66.7 volt drop across the first resistor and a 33 volt drop across the two resistors in parallel.

If you remove on of the 100 ohm resistors that is in parallel, the first resistor will have a 50 volt drop and the resistor remaining in from the two in parallel will have a 50 volt drop. 

So the potential difference in the parallel resistor if the other one is removed went from 33 volts to 50 volts.  It went up.