Question 1

Which equation correctly represents the equivalent resistance for three resistors $$R_1$$, $$R_2$$, and $$R_3$$ connected in series?

Accepted Answer

$$R_{eq} = R_1$ + R_2$ + R_3$

Question 2

In a parallel circuit with resistors $$R_1$$, $$R_2$$, and $$R_3$$, which statement is true about the potential difference across each resistor?

Accepted Answer

The potential difference is the same across each resistor.

Question 3

A circuit contains a 12 V battery and two resistors, $$R_1 = 4$$\ \Omega$$ and R_2$ = 8\ \Omega$$, in series. What is the current through the circuit?

Accepted Answer

$$0.5\ 	ext{A}$$

Question 4

Which equation gives the equivalent resistance for three resistors $$R_1$$, $$R_2$$, and $$R_3 in $$parallel?

Accepted Answer

$$\frac{1}{R_{eq}} = \frac{1}{R_1$} + \frac{1}{R_2$} + \frac{1}{R_3$}$$

Question 5

If two identical light bulbs are connected in series to a battery, compared to connecting them in parallel, what happens to their brightness?

Accepted Answer

They glow less brightly in series than in parallel.

Question 6

A circuit has $$R_1 = 2$$\ \Omega$$ in series with a parallel combination of R_2$ = 4\ \Omega$$ and $$R_3 = 4$$\ \Omega$$. What is the equivalent resistance?

Accepted Answer

$$4\ \Omega$$

Question 7

Kirchhoff’s junction rule states that:

Accepted Answer

The sum of the currents into any junction equals zero.

Question 8

Which analogy best describes Kirchhoff’s junction rule?

Accepted Answer

The flow rate of water entering a pipe equals the flow rate leaving it.

Question 9

Kirchhoff’s loop rule is mathematically expressed as:

Accepted Answer

$$\sum V = 0$$

Question 10

When applying Kirchhoff’s loop rule, what sign should be used for the potential difference across a resistor when traveling in the direction of the current?

Accepted Answer

Negative ($$-IR)$$

Question 11

A galvanometer is used in which type of electrical instrument?

Accepted Answer

In both ammeters and voltmeters

Question 12

How does an ohmmeter measure resistance?

Accepted Answer

By using a battery, a variable resistor, and a meter in series

Question 13

A potentiometer can be used to measure the emf of a source without drawing any current. Why is this advantageous?

Accepted Answer

It prevents the source from being discharged during measurement.

Question 14

In an R-C circuit, the time constant $$	au is $$given by:

Accepted Answer

$$	au = RC$$

Question 15

The charge $$q on a $$capacitor in a charging R-C circuit as a function of time $$t is$$:

Accepted Answer

$$q = Q_0$ (1 - e$$^{-t/RC}$$)$$

Question 16

During the discharge of a capacitor in an R-C circuit, the current $$i as a $$function of time $$t is$$:

Accepted Answer

$$i = I_0$ e$$^{-t/RC}$$

Question 17

Why is it safer to use a three-prong plug in household wiring?

Accepted Answer

It provides a path for excess current to flow safely to ground.

Question 18

What is the primary function of a fuse in a household circuit?

Accepted Answer

To break the circuit when the current exceeds a safe value.

Question 19

A circuit breaker differs from a fuse in that:

Accepted Answer

It can be reset after tripping.

Direct-Current Circuits: Series, Parallel, Kirchhoff’s Rules, and Applications

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