Q: A resistor is color-coded with green, blue, red, and silver bands. What is its resistance and tolerance?

$$5.6\ \text{k}\Omega$$ with $$\pm 10\%$$ tolerance

Question 1

A flashlight uses a battery to power a bulb. Which of the following best describes the role of the battery in the circuit?

Accepted Answer

It acts as a source of electromotive force (emf), maintaining a potential difference across the bulb.

Question 2

Which equation correctly relates the current $$I$$, the charge $$Q$$, and time $$t in a $$conductor?

Accepted Answer

$$I = \frac{dQ}{dt}$$

Question 3

A copper wire and an aluminum wire have the same length and cross-sectional area. If the same potential difference is applied across both, which wire will carry more current? (Resistivity of copper is less than that of aluminum.)

Accepted Answer

The copper wire will carry more current.

Question 4

Which of the following best describes the direction of conventional current in a metallic conductor?

Accepted Answer

It is the direction positive charges would move, opposite to the actual electron flow.

Question 5

The resistivity $$\rho of a $$material is defined as:

Accepted Answer

$$\rho = \frac{E}{J}$$

Question 6

A 0.900-V potential difference is maintained across a 1.50-m length of tungsten wire with a cross-sectional area of $$0.600\ 	ext{mm}^2. $$The resistivity of tungsten is $$5.6 	imes 10$$^{-8}$$\ \Omega\cdot	ext{m}. $$What is the current in the wire?

Accepted Answer

$$0.016\ 	ext{A}$$

Question 7

Which of the following statements about Ohm’s Law is correct?

Accepted Answer

Ohm’s Law states that $$V = IR$$ only if the resistance $$R is $$constant.

Question 8

A resistor is color-coded with green, blue, red, and silver bands. What is its resistance and tolerance?

Accepted Answer

$$5.6\ 	ext{k}\Omega$$ with $$\pm 10\%$$ tolerance

Question 9

If the temperature of a metallic conductor increases, what generally happens to its resistivity?

Accepted Answer

The resistivity increases.

Question 10

A battery has an emf $$\mathcal{E}$$ and internal resistance $$r. If it is $$connected to an external resistor $$R$$, what is the current in the circuit?

Accepted Answer

$$I = \frac{\mathcal{E}}{R + r}$$

Question 11

Which of the following is true for an ideal voltmeter?

Accepted Answer

It has infinite resistance and should be connected in parallel with the circuit element being measured.

Question 12

Which of the following is true for an ideal ammeter?

Accepted Answer

It has zero resistance and should be connected in series with the circuit element being measured.

Question 13

In a circuit, the rate at which energy is delivered to a resistor is given by which of the following equations?

Accepted Answer

$$P = I^2$ R$$

Question 14

Two copper wires of different diameters are joined end to end, and a current flows through them. When electrons move from the larger-diameter wire into the smaller-diameter wire, what happens to their drift speed?

Accepted Answer

Their drift speed increases.

Question 15

In the circuit shown, two identical bulbs A and B are connected in series. Compared to bulb A, how does bulb B glow?

Accepted Answer

Bulb B glows just as brightly as bulb A.

Question 16

If bulb B is removed from a series circuit containing two identical bulbs A and B, and the circuit is completed so that only bulb A remains, how does the brightness of bulb A change?

Accepted Answer

Bulb A becomes brighter.

Question 17

Which of the following best describes the net change in electric potential for a round trip in a closed circuit?

Accepted Answer

The net change in potential is zero.

Question 18

A beaker of salt solution is connected in a circuit with a light bulb. The bulb glows when the solution is poured in. What does this demonstrate about current in solutions?

Accepted Answer

Current in solutions is carried by both positive and negative ions.

Question 19

Which of the following equations gives the resistance $$R of a $$wire of length $$L$$, cross-sectional area $$A$$, and resistivity $$\rho$$?

Accepted Answer

$$R = \frac{\rho L}{A}$$

Current, Resistance, and Electromotive Force (EMF): Study Notes

스터디 가이드 - 연습 문제

학습 가이드 - 플래시카드