Choose true or false for each statement regarding the resistance of a wire. O While maintaining a constant voltage V, the current I increases when the resistivity p of a wire decreases. While maintaining a constant voltage V, the current I increases when the cross-sectional area A of a wire expands. The resistance is inversely proportional to the cross-sectional area A of the wire.

-gauge copper wire has a diameter of 9.266 mm. Calculate the power loss in a kilometer of such wire when it carries 1.00102 A.

Consider a circuit that consists of a real battery with an emf and an internal resistance of r connected to a variable resistor R. (a) In order for the terminal voltage of the battery to be equal to the emf of the battery, what should the resistance of the variable resistor be adjusted to? (b) In older to get the maximum current from the battery, what should the resistance variable resistor be adjusted to? (c) In order for the maximum power output of the battery to be reached, what should the resistance of the variable resistor be set to?

An ECG monitor must have an KC time constant lessthan 1.00102s to be able to measure variations involtage oversmall time intervals, (a) If the resistance of the circuit (duemostly to that of the patient's chest) is 1.00kTwhat is the maximum capacitance of the circuit?(b) Would It be difficult in practice to limit the capacitance to less than the value found in (a)?

A 20.00-V battery is used to supply current to a 10-k resistor. Assume the voltage drop across any wires used for connections is negligible, (a) What is the current through the resistor? (b) What is the power dissipated by the resistor? (c) What is the power input from the battery; assuming all the electrical power is dissipated by the resistor? (d) What happens to the energy dissipated by the resistor?

A battery has an emf of 15.0 V. The terminal voltage of the battery is 11.6 V when it is delivering 20.0 W of power to an external load resistor R. (a) What is the value of R? (b) What is the internal resistance of the battery?

Consider the circuit shown in Figure P28.21 on page 860. (a) Find the voltage across the 3.00-0 resistor, (b) Find the current in the 3.00-12 resistor.

Wire B has twice the length and twice the radius of wire A. Both wires are made from the same material. If wire A has a resistance R, what is the resistance of wire B? (a) 4R (b) 2R (c) R (d) 12R (e) 14R

A 160F capacitor charged to 450 V is dischargedthrough a 31.2k resistor, (a) Find the time constant.(b)Calculate the temperature increase of the resistor, given that its mass is 2.50 g and its specific heat is 1.67kJ/kg °C,noting that most of the thermal energy is retained in the short time of the discharge, (c) Calculate the new resistance, assuming it is pure carbon. (d) Does this change in resistance seem significant?

(a) F ind the voltage drop in an extension cord having a 0.0600-O resistance and through which 5.00 A is flowing. (b) A cheaper cord utilizes thinner wire and has a resistance of 0.300 O. What is the voltage drop in it when 5.00 A flows? (c) Why is the voltage to whatever appliance is being used reduced by this amount? What is the effect on the appliance?