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Electric Power

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

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?


1. In alternating current, the motion of the charges a. continuously changes in the forward and reverse directions. b. is equal to the speed of light. c. is greater than the speed of light. d. in the direction of the electric field. 2. A flashlight bulb with a potential difference of 4.5 V ac

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

Drawing circuits. Complete with solution diagrams in bmp format.

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