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Electric Power

Application of Gauss' law

Consider a spherically symmetric configuration: A spherical charge distribution has radius R_A and *nonuniform* charge density rho(r) = rho_zero R_A / r. It is encircled by a conducting shell with inner radius R_B and outer radius R_C (R_A < R_B < R_C). Therefore, there are four regions: I. charged ball: 0 < r < R_A II.

13 Problems on electrostatics and current: Full discussions

1, True/False questions: State, in complete sentences, why your answer is wrong. 2, Multiple choice concept questions: Determine the correct answer and state, in complete sentences, why your answer was wrong and why the correct answer is correct. 3, Multiple choice problem questions: Determine the correct answer by work

Seven physics problems

(See attached file for full problem description) --- 1. A parallel-plate air capacitor has a capacitance of 920 pF. The charge on each plate is 2.55µC a. What is the potential difference between the plates? b. If the charge is kept constant, what will be the potential difference between the plates if the separation is doubl

Electrical extension cords

2. It is generally dangerous to tuck electrical extension cords away behind furniture, under carpets, or anywhere else that they might cause a fire. It's the same reason why electric heating elements on stoves or in room heaters operate. What principle is involved and how does it operate in each of these situations? 3.

Electric Current

1. A charge of 1020 C was passed through a wire in 5.5 min. What was the average electric current during that interval? 2. How long does it take for 67 C to pass a given point in a wire that carries an electric current of 0.80 A? 3. What is the potential difference across a 220 ohm resistor when a current of 3.50 A flow th


1. When a charge of 180 microC is applied to the plates of a capacitor, the potential difference between the plates is 15 V. What is the capacitance? 2. How much charge is stored on each plate of a 5000 MicroF capacitor whose plates are held at a potential difference of 350 V? 3.Calculate the capacitance of two flat metal

Uniform electric field

A uniform electric field produces an acceleration (10 m/s^2, 10 m/s^2,0) at (1 m, 1m, 1m) for a -5 micro Coloumb charge of mass 10 g. Write the electric field at all points in space. (Hint: it would be a good idea to know what uniform means here).

Current, Potential Difference and Resistance Questions

1. If a lamp is measured to have a resistance of 45 ohm when it operates at a power of 80 W, what is the current in the lamp? A. 2.10 A B. 1.3 A C. 0.91 A D. 0.83 A 2. If a lamp has a resistance of 120 ohm when it operates at a power of 1.00 x 10^2 W, what is the potential difference across the lamp?

Find the Horsepower Rating of a Car

An electric car accelerates for 8.0 seconds by drawing energy from its 290 V battery pack. During this time, 1280 Coulombs of charge pass through the battery pack. Find the minimum horsepower rating of the car. Answer in horsepower.

Voltage difference of a space station module shaped like a cylinder

Imagine a space station module shaped like a cylinder 30 m long and 5 m diameter orbiting close to the earth above the earth's equator. What would be the maximum potential difference that could develop between the ends of the module? How would the module have to be oriented to get this maximum voltage difference? Could this v

Working with the electric field between 2 parallel plates

Imagine to circular flat plates of radius R that are separated by a small distance s. Imagine that we connect the plates to a power supply that puts opposite charges on the plates of whatever magnitude Q is necessary to set up a fixed potential difference (delta*sigma) between them. A) argue that the magnitude of the total f

Energy to Increase Temperate of Lake

Lake Erie contains roughly 4.30 * 10^11 m3 of water. How many years would it take, using the full output of a 1,070 MW electric power plant, to raise the temperature of that volume of water from 10.8 °C to 12.2 °C?

Drawing circuits with Bulb and Dry cells

Draw a flashlight bulb and show where the current usually enters and leaves. Draw a D-Cell and label its two terminals. Now draw a diagram showing how to connect the bulb and cell with two lengths of wire. How might you connect them with one wire? Show the path of the current in each case.

Direct Currents

Multiple Choice 1. The resistance of a superconducting material drops, essentially to zero, rather suddenly when: (a) the sample is heated above Tc (b) the sample is exposed to a magnetic field (c) the sample is cooled below Tc (d) the sample experiences a current Ic (e) none of these. Explain your choice. 2. Imagine a len