A battery with EMF = AVb and internal resistance r is attached to the circuit shown with resistors R, and R2, and a switch. When the switch is open the current from the battery is lo and when the switch is closed the current from the battery is lc. What is the EMF? R1 = 12.9 Ohms, R2 = 21.0 Ohms, lo = 0.29 Amps, lc = 0.52 Amps Give your answer in Volts to at least three significant digits. Grade Scope Solution: Your Grade Scope solution should show your work and provide an equation for A Vb in terms of ONLY the variables R1, R2, lo, and lc. You may not need to use all these variables in your answer. Your Grade Scope solution should NOT INCLUDE THE NUMBERS given above. RI AVb H