Electricity Currents and Circuits

What is the resistance of a resistor if the potential difference across the resistor is 4.0 V when a current of 10.0 A flows through the resistor?

0.40 Ω

A light bulb has a resistance of 240 Ω when operating at 120 V. What is the current in the light bulb?

0.50 A

A flashlight bulb with a potential difference of 4.5 V across it has a resistance of 8.0 Ω. How much current is in the bulb filament?

0.56 A

A 120.0 Ω resistor, a 60.0 Ω resistor, and a 40.0 Ω resistor are connected in parallel and placed across a 12.0 V battery. What is the current of the entire circuit?

0.600 A

If a 75 W light bulb operates at a voltage of 120 V, what is the current in the bulb?

0.62 A

Three resistors of 3.3 k,Ω 4.7 kΩ, and 3.9 kΩ are connected in a series across a 12 V battery. What is the current through the resistors?

1.0 x 10-³ A

A 20.0 Ω resistor and a 40.0 Ω resistor are connected in series across a battery. If the current is 2.00 A, what is the voltage of the battery?

1.20 x 10² V

The amount of charge that moves through the filament of a light bulb in 2.00 s is 2.67 C. What is the current in the light bulb?

1.33 A

(Figure contains: 10.0 Ω, 10.0 Ω, 16 Ω, 8.0 Ω, 8.0 Ω, and 60.0 V) What is the equivalent resistance of the resistors in the figure shown above?

10 Ω

If a lamp has a resistance of 136 ohms when it operates at a power of 1.00 × 10^2 watts, what is the potential difference across the lamp?

117 V

A student makes a voltage divider from a 45 V battery, a 475 kΩ resistor, and a 235 kΩ resistor. When the output is measured across the smaller resistor, what voltage is shown?

15 V

What is the quantity of charge that passes through a conductor when there is a current of 0.25 A for 10 minutes?

150 C

A 10.0 ohm resistor, 20.0 ohm resistor, and a 25.0 ohm resistor are connected in series across a 110 V supply. Calculate the current in the circuit.

2.0 A

3.0Ω 3.0Ω◼️3.0Ω 3.0Ω What is the equivalent resistance for the resistors in the figure shown above?

2.2 Ω

The potential difference across a resistor is 4.4 × 10 V. If the resistance of the resistor is 1.8 kΩ, how much current flows through the resistor?

2.4 x 10^2 A (wrong)

A current of 8.0 A flows through a resistor when a potential difference of 20.0 V is applied to the resistor. What is the resistance of the resistor?

2.50 Ω

What is the potential difference across a 5.0 Ω resistor that carries a current of 5.0 A?

25 V

The current in an electron beam in a cathode-ray tube is 7.0 × 10^-5 A. How much charge hits the screen in 5.0 s?

3.5 x 10^-4 C

Two resistors with values of 6.0 Ω and 12 Ω are connected in parallel. This combination is connected in series with a 2.0 Ω resistor and a 24 V battery. What is the current in the 2.0 Ω resistor?

4.0 A

A 2.0 V battery is connected in a circuit with an ammeter and an unknown resistor, P. The current is observed to be 0.70 A. What would be the current in the circuit if a 12 V battery replaces the 2.0 V battery?

4.2 A

A 4.7 x 10 Ω resistor has a current of 1.27 x 10^-1 A flowing in it. What is the potential difference across the resistor?

4.8 V (wrong)

Three resistors of 1.00 x 10² Ω, 3.90 x 10³ Ω, and 1.00 x 10³ Ω are connected in series across a 2.00 x 10² V battery. What is the voltage drop across the resistor of value 1.00 x 10³ Ω?

40.0 V

Two resistors with values of 6.0 Ω and 12 Ω are connected in parallel. This combination is connected in series with a 4.0 Ω resistor. What is the equivalent resistance of this combination?

8.0 Ω

Tripling the current in a circuit with constant resistance has the effort of changing the power by what factor?

9

If a 325 W heater has a current of 6.0 A, what is the resistance of the heating element?

9.0 Ω

When a potential difference of 13 V is placed across a resistor, the current in the resistor is 1.4 A. What is the resistance of the resistor?

9.3

Electric circuit

A closed loop or pathway that allows electric charges to flow.

Battery

A device made up of several galvanic cells connected together that converts chemical energy to electric energy.

Resistor

A device with a specific resistance; may be made of long, thin wires, graphite, or semiconductors and often is used to control the current in circuits or parts of circuits.

Electric current

A flow of charged particles.

Ampere

A flow of electric charge, or electric current, equal to one coulomb per second (1C/s).

Conventional current

A flow of positive charges that move from higher potential to lower potential.

Resistance

A property that determines how much current will flow; is equal to voltage divided by current.

Parallel connection

A type of connection in which the circuit component and the voltmeter are aligned parallel to one another in the circuit, the potential difference across the voltmeter equals the potential difference across the circuit, and there are two or more paths.

Series connection

A type of connection in which there is only a single current path.

A bulb connected to a 12-V battery and a current of 0.3 A is measured in the bulb. A. Calculate the resistance of the bulb. B. If the bulb is connected to a 24-V battery, the current is measured to be 0.50 A. What is the resistance of the bulb?

A. 40 Ohms B. 48 Ohms

How is the voltage of the power supply for a series circuit calculated?

Add the voltage of each component in the series.

An operating (turned on) lightbulb has a resistance that is about 10 to 20 times greater than when it is not operating (turned off). How does this explain why lightbulbs often burn out at the moment they are turned on?

At the instant the bulb is turned on, the lower resistance results in a current through the bulb that is 10 to 20 times greater than the operating current. This high current may cause physical damage to the filament in the bulb.

Why is a bird able to sit on a power line?

Because the line is covered with insulating material. (wrong)

The table below shows a list of some electric appliances with the values of their potential differences and current. Which appliance consumes the most power? - Television: 24 V, 0.75 A - Drill: 110 V, 1.6 A - Bulb: 12 V, 4.0 A - Amplifier: 110 V, 0.2 A

Drill

What is electric current?

Electric current is the rate at which electric charges move through an area.

What are some applications of electric current?

Electric current powers lights and home appliances. It also ignites the gasoline in automobile engines, and it us used in microcomputers.

In any complex resistance circuit, the voltage across any resistor in the circuit is always

Equal to or less than the voltage source.

The first step to finding the current in a complex circuit is to determine the _________.

Equivalent resistance of the circuit.

Using a 1-kW heater for one hour consumes more energy than using a 100-W bulb for twenty-four hours.

False

A device that detects small current differences and prevents electrocution that is often required as a safety measure for bathroom, kitchen, and exterior outlets.

Ground-fault interrupter

The number of current paths in a series circuit is:

One.

What formula is used to calculate resistance using the color code?

R = (First digit * 10 + second digit) * multiplier.

The power ratings on light bulbs are measures of the

Rate that they give off heat and light.

If a resistor is added to a parallel circuit, the equivalent resistance:

Remains the same (wrong)

With regard to the flow of electric current, what is resistance?

Resistance is the opposition to electric current by a material or device.

In a parallel circuit, less ______ produces the most _______, because it draws the most current.

Resistance, heat.

There is a 0.40 A current in resistor X when it is connected to a 2.0 V battery. A 0.25 A current is in a second resistor, Y, when it is connected to a 4 V battery. There is a 0.50 A current in the third resistor, Z, when it is connected to a 5.0 V battery. Find the resistor that has the maximum resistance and the resistor that has the least resistance.

Resistor Y has the maximum resistance, while resistor X has the least resistance.

What is the SI unit for current?

The ampere (A) is the SI unit for current.

How is current affected if the time interval over which the charge passes through a given area decreases while the amount of charge remains the same?

The current increases.

Which set of information will allow you to calculate the kilowatt*hr usage?

The resistance, the current, and the time the circuit operates.

What are the components of an electrical circuit?

a battery or generator, a wire, and a motor or load.

A bolt of lightning discharges 9.7 C in 8.9 × 10^-4 s. What is the average current during the discharge?

1.1 x 10^4 A

A steam turbine at an electric power plant delivers 4500 kW of power to an electrical generator that converts 95% of this mechanical energy into electrical energy. What is the current delivered by the generator if it delivers energy at 3600 V?

1.2 x 10^3 A

An electric toaster requires 1100 W at 110 V. What is the resistance of the heating coil?

11 Ω

A 4.0 ohm resistor, an 8.0 ohm resistor, and a 10.0 ohm resistor are connected in series across an 11 V battery. The total voltage drop across the 4.0 ohm and 8.0 ohm resistors is:

6.0 V

When compared in a given time interval with other light bulbs connected to a 120 V circuit, a 60 W lightbulb

Converts less electrical energy to heat and light than a 100 W light bulb.

A short piece of metal that melts when a large current passes through it is a:

Fuse.

If a resistor is added to a series circuit, the equivalent resistance:

Increases.

Is it possible to find the voltage of the second lamp in a parallel circuit if one lamp has a voltage of 12 V?

Yes