BackTwo resistors are made of the same material, one twice as long as the other. If the current through the shorter resistor is 5 A, what is the current through the longer resistor if they both have the same potential difference and cross-sectional area?
A copper transmission cable km long and cm in diameter carries a current of A. How much electrical energy is dissipated as thermal energy every hour?
What is the resistance of a carbon rod at °C if its resistance is at °C?
A hollow aluminum cylinder is m long and has an inner radius of cm and an outer radius of cm. Treat each surface (inner, outer, and the two end faces) as an equipotential surface. At room temperature, what will an ohmmeter read if it is connected between (a) the opposite faces and (b) the inner and outer surfaces?
In household wiring, copper wire mm in diameter is often used. Find the resistance of a -m length of this wire.
A ductile metal wire has resistance . What will be the resistance of this wire in terms of if it is stretched to three times its original length, assuming that the density and resistivity of the material do not change when the wire is stretched? (Hint: The amount of metal does not change, so stretching out the wire will affect its cross-sectional area.)
A cylindrical tungsten filament cm long with a diameter of mm is to be used in a machine for which the temperature will range from room temperature (°C) up to °C. It will carry a current of A at all temperatures. What will be the maximum potential drop over the full length of the filament?
A 1.5 V battery provides 0.50 A of current. At what rate (C/s) is charge lifted by the charge escalator?
Electrical engineers sometimes use a wire's conductance, G=σA/L, instead of its resistance. A 1.5 A current flows through the wire of part b. What is the potential difference between the ends of the wire?
A 0.0075 V/m electric field creates a 3.9 mA current in a 1.0-mm-diameter wire. What material is the wire made of?