6.1 MCAS Electromagnetism Questions

How much voltage is needed to produce a current of 6.0 A through a 24 Ω resistor?

• 4 V

• 18 V

• 30 V

• 144 V

A short copper rod has a neutral charge. Negative charges are then applied to the right end of the rod.

Which of the following describes the charge on the copper rod 5 s later?

• Both ends of the rod have a positive charge.

• The negative charge is spread evenly along the rod.

• Only the right end of the rod has a negative charge.

• All of the positive charge is in the middle of the rod.

A load uses a current of 5.0 A when it is attached to a 20 V source. What is the resistance of the load?

• 0.25 Ω

• 1.25 Ω

• 4.0 Ω

• 15.0 Ω

Negatively charged plastic rods are brought near a plastic sphere and a metal sphere without touching the spheres. Which of the following diagrams best illustrates the resulting distribution of the negative charges on the two spheres?

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A circuit has three different resistors and a battery. One of the resistors has a resistance of 10 Ω. A student wants to calculate the current flowing through this resistor.

Which of the following would provide the student with enough information to calculate the current in the 10 Ω resistor?

• the arrangement of the circuit

• the power rating of the battery

• the voltage across this resistor

• the values of the other two resistors

What is the primary difference between insulators and conductors?

• Electrons are present in insulators but not in conductors.

• Electrons are present in conductors but not in insulators.

• Electrons are free to move in insulators but not in conductors.

• Electrons are free to move in conductors but not in insulators.

Which of the following circuits has the greatest current?

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A clothes iron is designed to be used with a 220 V outlet. Which of the following will happen if the iron is plugged into a 110 V outlet instead of a 220 V outlet?

• The iron will exceed its maximum power rating.

• The internal resistance of the iron will increase.

• The iron will use the same energy for a given amount of time.

• The current delivered to the iron will be lower than the maximum amount.

When an uncharged balloon is rubbed against dry uncharged hair, electrons move from the hair onto the balloon’s surface. Which table lists the charges of the balloon and the hair after they are moved apart?

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The graph below shows the relationship of voltage versus current for a circuit.

This graph represents the relationship described by which of the following laws?

• Coulomb’s law

• Doppler’s law

• Newton’s law

• Ohm’s law