10.27: The circuit shown contains a batter+fetum6p/kctde0h; wne1 *;v y (of emf $V_bat$) with an internal resistance r connected to a rheostat (variable resistor). When the resistance of the rheostat is increased, which of the following statements is true?

  12.39: For the circuit shox8l6cg:ki ( yswn, all wires have no resistance, the battery has a constant inlkg (s :6xyc8iternal resistance of $r = 8.0Ω$ and the two lightbulbs (#1 and #2) are identical, each with resistance R bulb. The variable resistor is initially setto $R = 26.0Ω$ . The switch in the circuit now is closed. To what resistance must the variable resistor be set if bulb #1 is to have the same brightness after the switch is closed as it did with the switch open?