PHY2044 - PHYSICS FOR ENGINEERS II
PRACTICE TEST FOR CHAPTER 25

Below you will find a set of 5 conceptual and numerical revision questions selected randomly from lots of questions I have put together covering the material in Chapter 25, "Electric Current and Direct-Current Circuits". This includes questions on electrical current, resistance, Ohm's Law, energy in circuits, combinations of resistors, Kirchhoff's rules and R-C circuits. When you have finished the quiz, click on the "Submit Quiz" button at the bottom and within seconds it will be automatically graded and the results returned to you!

To select a new set of questions click on the "Reload" or "Refresh" button on your browser. You may find some of the questions duplicated but that's the nature of a random selection. Try it a few times ... it's not fattening and you may learn something!

Many thanks to Mark Wood for producing the quiz-maker code.


Q1:

Which of the following relations among the quantities in the figure is generally correct?

I1R1 = I2R2
I3R3 = I4R4
I1R1 = I4R4
I3R4 = I4R3
I1R1 + I2R2 = E


Q2: A battery is connected to a series combination of a switch, a resistance, and an initially uncharged capacitor. The switch is then closed. Which of the following is correct?

As the charge on the capacitor increases, the current increases.
As the charge on the capacitor increases, the current remains constant.
As the charge on the capacitor increases, the potential difference across the resistance increases.
As the charge on the capacitor increases, the potential difference across the capacitor decreases.
As the charge on the capacitor increases, the potential difference across the resistance decreases.

Q3: A 20 μF capacitor is charged to 200 V and is then connected across a 1000 Ω resistor. What is the initial current just after the capacitor is connected to the resistor?

100 mA
200 mA
150 mA
300 mA
50 mA

Q4: An uncharged capacitor and a resistor are connected in series to a battery as shown below.

If E = 15 V, C = 20 μF, and R = 4.0 × 105 Ω, the maximum current in the circuit is appproximately

38 μA
75 μA
19 μA
56 μA
33 μA


Q5: An uncharged 5.0 μF capacitor and a resistor are connected in series to a 12 V battery to form a simple RC circuit as shown below at the left. The switch is closed at t = 0. The graph at the right shows the time variation of the current through the resistor. The time constant of the circuit is 4.0 s.

What is the maximum charge on the capacitor?

5.5 μC
9.5 μC
15 μC
48 μC
60 μC


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