1) In the circuit at right the resistors are: r-192 R-402 R-302 R-62 R-202 Ks-160 The...

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1) In the circuit at right the resistors are: r-192 R-402 R-302 R-62 R-202 Ks-160 The current /, is 2.0 A. Battery 8, is a real battery which has an internal resistance r and an unknown emf &, while battery B, is an ideal battery with &, -2.0 V. B & 352 ww 102252 Rs Ra 4 B a) Draw and name all currents on the diagram. Use Kirchhoff's laws to write equations. b) Solve the equations to find the value of each current, and list them (they should all be integer or simple fractional values). Note: by sliding junction points and combining certain elements you can simplify the appearance of the circuit and reduce the number of loops, and therefore the number of currents. Of course, once you find the reduced number of currents you will need to go back and find the currents through any elements you had combined. c) What is the emf &, of battery B? d) Taking the potential at point a to be zero, find the potential at points b, c, d, e, f, and g. What is the terminal voltage (nor the emf) of battery B, under these conditions? Suggestion: Double check the potential at each junction by adding up potential changes along all possible routes, to make sure they agree. If they do not all agree you have an error, most likely in your currents. The most common error is a wrong sign for one of the terms in a loop equation, so that is probably the first place to look. e) Calculate the power produced, stored, or dissipated by every device (batteries, resistors, ammeters) in the circuit except for battery B. Pay close attention to the sign of the power produced or stored for devices that are not dissipative (resistors dissipate rather than store energy). 1) What is the power produced by chemical reactions in battery B? g) What is the net usable power produced by battery B? h) What is the total power dissipated by the resistors? How does this compare to your answers for the previous two questions? Explain. i) If R, is increased what will happen to the current in R,? Use this result to deduce how the voltage at point c will change and therefore whether the current in R, will increase or decrease. Will the current in R, increase or decrease? 1) In the circuit at right the resistors are: r-192 R-402 R-302 R-62 R-202 Ks-160 The current /, is 2.0 A. Battery 8, is a real battery which has an internal resistance r and an unknown emf &, while battery B, is an ideal battery with &, -2.0 V. B & 352 ww 102252 Rs Ra 4 B a) Draw and name all currents on the diagram. Use Kirchhoff's laws to write equations. b) Solve the equations to find the value of each current, and list them (they should all be integer or simple fractional values). Note: by sliding junction points and combining certain elements you can simplify the appearance of the circuit and reduce the number of loops, and therefore the number of currents. Of course, once you find the reduced number of currents you will need to go back and find the currents through any elements you had combined. c) What is the emf &, of battery B? d) Taking the potential at point a to be zero, find the potential at points b, c, d, e, f, and g. What is the terminal voltage (nor the emf) of battery B, under these conditions? Suggestion: Double check the potential at each junction by adding up potential changes along all possible routes, to make sure they agree. If they do not all agree you have an error, most likely in your currents. The most common error is a wrong sign for one of the terms in a loop equation, so that is probably the first place to look. e) Calculate the power produced, stored, or dissipated by every device (batteries, resistors, ammeters) in the circuit except for battery B. Pay close attention to the sign of the power produced or stored for devices that are not dissipative (resistors dissipate rather than store energy). 1) What is the power produced by chemical reactions in battery B? g) What is the net usable power produced by battery B? h) What is the total power dissipated by the resistors? How does this compare to your answers for the previous two questions? Explain. i) If R, is increased what will happen to the current in R,? Use this result to deduce how the voltage at point c will change and therefore whether the current in R, will increase or decrease. Will the current in R, increase or decrease?

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