Copy of Physics - Chapter 19 - Electrical Circuits

You connect a resistor across a battery. In which direction do the electrons flow?

• A. The electrons flow from the negative terminal of the battery to the positive terminal of the battery.
• B. The electrons flow from the positive terminal of the battery to the negative terminal of the battery.

How does current depend on resistance in Ohm’s law?

• A. Current is directly proportional to the resistance.
• B. Current is inversely proportional to the resistance.
• C. Current is proportional to the square of the resistance.
• D. Current is inversely proportional to the square of the resistance.

In the context of electricity, what is resistance?

• A. Resistance is the property of materials to resist the passage of voltage.
• B. Resistance is the property of materials to resist the passage of electric current.
• C. Resistance is the property of materials to increase the passage of voltage.
• D. Resistance is the property of materials to increase the passage of electric current.

What is the mathematical formula for Ohm’s law?

• A. V = I^2R
• B. V = R/I
• C. V = I/R
• D. V = IR

An accelerator accelerates He nuclei (change = 2e) to a speed of v = 2 × 10^6 m/s. What is the current if the linear density of He nuclei is λ = 108 m^–1?

• A. I = 9.6 × 10^–5 A
• B. I = 3.2 × 10^–5 A
• C. I = 12.8 × 10^–5 A
• D. I = 6.4 × 10^–5 A

How can you verify whether a certain material is ohmic?

• A. Make a resistor from this material and measure the current going through this resistor for several different voltages. If the current is proportional to the voltage, then the material is ohmic.
• B. Make a resistor from this material and measure the current going through this resistor for several different voltages. If the current is inversely proportional to the voltage, then the material is ohmic.
• C. Make a resistor from this material and measure the current going through this resistor for several different voltages. If the current is proportional to the square of the voltage, then the material is ohmic.
• D. Make a resistor from this material and measure the current going through this resistor for several different voltages. If the current is inversely proportional to the square of the voltage, then the material is ohmic.

What voltage is needed to make 6 C of charge traverse a 100-Ω resistor in 1 min?

• A. The required voltage is 1 × 10^−3 V.
• B. The required voltage is 10 V.
• C. The required voltage is 1,000 V.
• D. The required voltage is 10,000 V.

Resistors typically obey Ohm’s law at low currents, but show deviations at higher currents because of heating. Suppose you were to conduct an experiment measuring the voltage, V, across a resistor as a function of current, I, including currents whose deviations from Ohm’s law start to become apparent. For a data plot of V versus I, which of the following functions would be best to fit the data? Assume that a, b, and c are nonzero constants adjusted to fit the data.

• A. V=aI
• B. V=aI+b
• C. V=aI+bI^2
• D. V=aI+bI^2 +c

A battery of unknown voltage V_1 is attached across a resistor R_1. You add a second battery with V_2 = 9.0 V in series with V_1 so that the voltage across R_1 is now V_1 + V_2 and measure 0.3 A of current through resistor R_1. You add a third battery with V_3 = 9.0 V in series with the first two batteries so that the voltage across R_3 is V_1 + V_2 + V_3 and measure 0.4 A of current through R_1. What is the resistance of R_1?

• A. 23.25 Ω
• B. 21.75 Ω
• C. 31.33 Ω
• D. 13.0 Ω

In which circuit are all the resistors connected in series? See the circuits below:

• A.
• B.
• C.
• D.