Physics 4Q

When a current flows through the coil of an ammeter placed in a magnetic field, what will happen to the needle of the ammeter?

• It will be reflected.

• It will be deflected.

• It will be refracted.

• All of the above

The following are non-ohmic materials, EXCEPT:

• Silicon

• Tin

• Diode

• Copper

A small electric heater uses a 10-ohm resistor to convert electrical energy into heat. The current flowing through the resistor is 2 A. How much power is being dissipated as heat by the resistor in the heater?

• 5W

• 10W

• 20W

• 40W

Which device is used to measure current in a circuit?

• Voltmeter

• Ammeter

• Ohmmeter

• Wattmeter

Which of the following is an advantage of alternating current (AC) over direct current (DC) in power transmission?

• AC can be easily converted to different voltages using transformers.

• DC is more efficient for long-distance power transmission.

• AC is easier to store in batteries.

• AC is less dangerous than DC for power transmission.

A pocket calculator uses solar cells to generate electricity. The calculator's solar cells deliver a charge of 4.00 C over a time period of 4.00 hours. What is the current (in milliamperes) produced by the solar cells in the calculator?

• 0.278 mA

• 0.479 mA

• 0.176 mA

• 0.200 mA

You are working on a small electrical project, and a charge of 30 C is being transferred through a wire in 10 seconds. This setup is part of a simple circuit powering a light bulb: What is the current flowing through the wire that powers the light bulb?

• 3A

• 10A

• 5A

• 0.3A

Which property describes the resistance to the flow of electric current in materials, where some materials resist the current flow more than others?

• Insulators

• Conductivity

• Resistance

• Resistivity

Which material has the highest resistivity?

• Copper

• Rubber

• Aluminum

• Silver

In a laboratory experiment, you're tasked with investigating how the resistance of a wire changes when the cross-sectional area is altered. You have two wires made of the same material and with the same length, but one wire has a thicker cross-section than the other. If you increase the cross-sectional area of a conductor, what will happen to its resistance?

• Increase

• Decrease

• Does not change

• Expand