Exam 22: Current and Resistance

The figure shows electrons passing through a resistor. The arrow shows the direction in which the electrons are moving. Which of the following statements are correct? (There could be more than one correct choice.)

When a current flows through an ionic liquid such as salty water, the moving charges are

If the current flowing through a circuit of constant resistance is doubled, the power dissipated by that circuit will

The figure shows conventional current passing through a resistor. The arrow shows the direction in which this conventional current is flowing. Which of the following statements are correct? (There could be more than one correct choice.)

What current is flowing in a resistor if 4.0 × 10¹⁶ electrons pass a point in the resistor in 0.50 s? (e = 1.60 × 10^-19 C)

If a quantity you calculated has units of Ω ∙ m what is that quantity?

How much current will flow through a $40.0 - \mathrm { m }$ length of metal wire with a radius of $0.0 \mathrm {~mm}$ if it is connected to a power source supplying $16.0 \mathrm {~V} ?$ The resistivity of the metal is 1.68 × 10^-8 ? ? m.

A device with a resistance of $200.0 \mathrm { k } \Omega$ is connected to a $10.0 - \mathrm { V }$ battery. How much power does the device use?

A jeweler needs to electroplate gold, having an atomic mass of 196.97 g/mol, onto a bracelet. He knows that the charge carriers in the ionic solution are singly-ionized gold ions, Au⁺, and has calculated that he must deposit $0.20 \mathrm {~g}$ of gold to reach the necessary thickness. How much current does he need to plate the bracelet in 3.0 hours? (e = 1.60 × 10^-19 C, N_A = 6.02 × 10²³ atoms/mol)

The nichrome heating element in an electric drier operates on 240 V and generates heat at the rate of 2.0 kW. The heating element shorts out and, in repairing it, the repairman shortens the nichrome wire by 10%. (Assume the temperature is unchanged. In reality, the resistivity of the wire will depend on its temperature.)What effect will the repair have on the power dissipated in the heating element?

The current through a piece of lab equipment must be limited to 2.75 A when it is run by a 120-V dc power supply. What must be the resistance of this equipment?

A 1500-W heater is connected to a 120-V line for 2.0 hours. How much heat energy is produced?

A 5.0-V battery storing 43.0 kJ of energy supplies $1.5 \mathrm {~A}$ of current to a circuit. How much energy does the battery have left after powering the circuit for $1.0 \mathrm {~h} ?$

A total of 2.0 × 10¹³ electrons pass a given point in a wire in 15 s. What is the current in the wire? (e = 1.60 × 10^-19 C)

In an electroplating process, it is desired to deposit 40 mg of silver on a metal part by using a current of 2.0 A. How long must the current be allowed to run to deposit this much silver? The silver ions are singly charged, and the atomic mass of silver is 108 g/mol. (e = 1.60 × 10^-19 C, N_A = 6.02 × 10²³ atoms/mol)

The power rating of a 400-? resistor is 0.800 W. (a)What is the maximum safe voltage across this resistor? (b)What is the maximum current the resistor can safely draw?

What current is flowing in a wire if 0.67 C of charge pass a point in the wire in 0.30 s?

If the power rating of a 400-Ω resistor is 0.80 W, what is the maximum current it can safely draw?

A certain metal has a resistivity of 1.68 × 10^-8 Ω ∙ m. You have a long spool of wire made from this metal. If this wire has a diameter of 0.15 mm, how long should you cut a segment so its resistance will be 15 Ω?

For the graph shown in the figure, what physical quantity does the slope of the graph represent for a dc circuit?