Electricity

What charge do electrons have in an atom?

• No charge

• Neutral

• Positive

• Negative

Answer explanation

Electrons have a negative charge in an atom.

Positive charges from from ___.

• low-resistance to high-resistance areas

• insulators to conductors

• low-voltage to high-voltage areas

• high-voltage to low voltage areas

Answer explanation

Positive charges flow from high-voltage to low-voltage areas, as stated in the correct answer choice.

Which transforms electrical energy to thermal energy?

• fuse

• battery

• resistor

• series circuit

Answer explanation

A resistor transforms electrical energy to thermal energy.

What is the standard voltage difference of electrical outlets in the U.S.?

• 220 volts

• 120 volts

• 240 volts

• 110 volts

Answer explanation

The standard voltage difference of electrical outlets in the U.S. is 120 volts. This is the correct choice.

What is needed to make an electric circuit?

• a light bulb

• conductive materials

• Battery

• a closed path

Answer explanation

An electric circuit requires a closed path to allow the flow of electricity. Without a closed path, the circuit would be incomplete and no current would flow.

What is the current in a circuit that has a resistance of 75 ohms and a voltage difference of 120 V?

• 0.8 A

• 4.8 A

• 2.4 A

• 1.6 A

Answer explanation

The current in the circuit can be calculated using Ohm's Law: I = V/R. Therefore, the current is 120 V / 75 ohms = 1.6 A. This matches the correct answer choice.

What is the power consumed by a lightbulb in a circuit that has a current of 1.6 A and a voltage difference of 120 V?

• 0.192 W

• 12 W

• 192 W

• 1920 W

Answer explanation

The power consumed by a lightbulb in a circuit is calculated using the formula P = IV, where P is power, I is current, and V is voltage. Therefore, the power consumed is 1.6 A * 120 V = 192 W. The correct answer is 192 W.

Why do electrical devices have resistance?

• Electrical devices have resistance because they are made of insulating materials

• Electrical devices have no resistance and always conduct electricity perfectly

• Electrical devices have resistance due to the absence of electrons in the material

• Electrical devices have resistance due to the collisions between electrons and atoms in the material, which converts electrical energy into heat.

Answer explanation

Electrical devices have resistance due to collisions between electrons and atoms, converting electrical energy into heat.

Voltage difference is measured in ___.

• volts (V)

• meters (m)

• seconds (s)

• grams (g)

Answer explanation

Voltage difference is measured in volts (V) because volts is the unit of measurement for voltage difference.

What is resistance?

• Resistance is the measure of opposition to the flow of electric current in a material.

• Resistance is the measure of speed of electric current in a material.

• Resistance is the measure of attraction to the flow of electric current in a material.

• Resistance is the measure of support to the flow of electric current in a material.

Answer explanation

Resistance is the measure of opposition to the flow of electric current in a material.