HW 3 Help please

of O zoom + Homework 3: Ch 17 Current Resistance 1. Use the gure below to calculate: 100v 4P1: EFF E a. What is the Equivalent Capacitance of this configuration? b. After the circuit has been connected for some time, howr much energy is stored in this combination of capacitors? 2. The current through a certain heater wire is found to be fairly independent of its temperature. If the current through the heater wire is doubled, the amount of energy delivered by the heater in a given time interval will a. increase by a factor of two. b. decrease by a factor of two. I:. increase by a factor of four. d. decrease by a factor of four. e. increase by a factor of eight. Please show your reasoning in either math or words. of O ZOOM + 3. Two lightbulbs are each connected to a voltage of 120 V. One has a power of 25 W, the other 100 W. a. Which lightbulb has the higher resistance? b. Which lightbulb carries more current? 4. A typical lightning bolt may last for 0.200 s and transfer 1.00x107-0 electrons. Calculate the average current in the lightning bolt. of O zoom + 5. A voltmeter connected across the terminals of a tungstenlament lightbulb measures 115 then an ammeter in line with the bulb registers a current of0.522 A. a. Find the resistance of the lightbulb. b. Find the resistivity of the tungsten at the bulb's operating temperature if the filament has an uncoiled length of 0.500 m and a radius of 2.300(105 m. 6. A person notices a mild shock if the current along a path through the thumb and index finger exceeds 80 NA. Compare the maximum possible voltage without shock across the thumb and index finger with a dryskin resistance of 4.0):10-5 and a wetskin resistance of 2x103 :1. 7. The human body can exhibit a wide range of resistances to current depending on the path of the current, contact area, and sweatiness of the skin. Suppose the resistance across the chest from the left hand to the right hand is 1.0x105 .0. a. How much voltage is required to cause possible heart fibrillation in a man, which corresponds to 500 mA of direct current? b. Why should rubbersoled shoes and rubber gloves be worn when worl-cing around electricity? Page 2 of 3 ZOOM 7. The human body can exhibit a wide range of resistances to current depending on the path of the current, contact area, and sweatiness of the skin. Suppose the resistance across the chest from the left hand to the right hand is 1.0x106 0. a. How much voltage is required to cause possible heart fibrillation in a man, which corresponds to 500 mA of direct current? b. Why should rubber-soled shoes and rubber gloves be worn when working around electricity? 2of O ZOOM + B. Atypical eeil phone consumes an average of about 1.00 W of electrical power and operates on 3.80 V. a. What average current does the phone draw from its battery? b. Calculate the energy stored in a fully charged battery ifthe phone requires charging after 5.00 hours of use. 9. A copper cable is designed to carry a current of 300 A with a power loss of 3.00 W/m. What is the required radius of this cable? 10. The potential difference across a resting neuron in the human body is about 75.0 mV and carries a current of about 0.200 mA. How much power does the neuron release