R4 R2 Rs. Vs R1 R3 Rs R- Rs

(a) defibrillator sends a 6 A current through the chest of a patient by applying a 11000 V potential as in the figure. What is the resistance of the path (through the wire and the body)? -aira R= (b) The defibrillator paddles make contact with the patient through a conducting gel that greatly reduces the path resistance. To understand the importance of using the gel, discuss the difficulties that would ensue if a larger voltage were used to produce the same current through the patient, but with the path having perhaps 50 times the resistance by finding the ratio, P no-gel P gel e- ΚΩ (Hint: The current must be about the same, so a higher voltage would imply greater power. Use this equation for power: P = PR.) What difficulties arise when no gel is used? a. The voltage is too high for the human body even when the current is the same. b. There is a risk of skin burns because of the high power deposited.

A potentiometer consisting of a wire of length L0 has a source of emf, ɛ connected across it. When a standard cell with emf V = 6V, in series with a voltmeter, is connected at one end of the wire and at a distance L = 4 cm along the wire the voltmeter circuit is in balance and the voltmeter reads zero. When the standard cell is replaced by a source of unknown emf the new balance length is found to be 6 cm. What is the unknown emf?       Select one: a. 9 V b. 8 V c. 4 V d. 3 V

Explore the concept of duality in electrical circuits, where voltage and current are dual variables. How does this concept apply to circuit analysis?