Q: A flashlight bulb is connected to a 3.0 V battery and draws a current of 0.40 A. How much energy is dissipated in the bulb in 5.5 minutes of operation?

$$E = IVt = (0.40\times 3.0\times 330) = 396\ \text{J}$$

Q: Two resistors, $$R_1 = 6.00$$\ \Omega$$ and R_2$ = 3.00\ \Omega$$, are connected in series to a 12.0 V battery. What is the current in the circuit?

$$I = \frac{12.0}{6.00 + 3.00} = 1.33\ \text{A}$$

Q: A LED bulb draws 0.083 A from a 120 V source. What is the power consumed by the bulb?

$$P = IV = 0.083\times 120 = 10\ \text{W}$$

Q: A car battery has an emf of 12.0 V and an internal resistance of 0.0100 $$\Omega. $$What is the terminal voltage when the current drawn is 100.0 A?

$$V_{\text{terminal}} = 12.0 - (100.0 \times 0.0100) = 11.0\ \text{V}$$

Q: If a battery with emf $$\mathcal{E}$$ and internal resistance $$r is $$connected to a load resistance $$R$$, what is the expression for the terminal voltage?

$$V_{\text{terminal}} = \mathcal{E} - Ir$$

Q: A circuit contains a 6.00 $$\Omega$$ and a 3.00 $$\Omega$$ resistor in series with a 12.0 V battery. What is the voltage across the 6.00 $$\Omega$$ resistor?

$$V = IR = 1.33 \times 6.00 = 8.0\ \text{V}$$

Q: In a parallel circuit with resistors $$R_1$$ and $$R_2$$, which formula gives the total current supplied by the battery?

$$I_{\text{total}} = I_1$ + I_2$

Question 1

A flashlight bulb is connected to a 3.0 V battery and draws a current of 0.40 A. How much energy is dissipated in the bulb in 5.5 minutes of operation?

Accepted Answer

$$E = IVt = (0.40	imes 3.0	imes 330) = 396\ 	ext{J}$$

Question 2

Which equation correctly expresses the electric power dissipated by a resistor in terms of its resistance $$R$$ and the voltage $$V$$ across it?

Accepted Answer

$$P = \frac{V^2$}{R}$$

Question 3

Two resistors, $$R_1 = 6.00$$\ \Omega$$ and R_2$ = 3.00\ \Omega$$, are connected in series to a 12.0 V battery. What is the current in the circuit?

Accepted Answer

$$I = \frac{12.0}{6.00 + 3.00} = 1.33\ 	ext{A}$$

Question 4

In a series circuit, which of the following statements is true?

Accepted Answer

The current is the same through all components.

Question 5

A LED bulb draws 0.083 A from a 120 V source. What is the power consumed by the bulb?

Accepted Answer

$$P = IV = 0.083	imes 120 = 10\ 	ext{W}$$

Question 6

Two resistors, $$R_1 = 8.00$$\ \Omega$$ and R_2$ = 4.00\ \Omega$$, are connected in parallel. What is the equivalent resistance?

Accepted Answer

$$R_P = \left(\frac{1}{8.00} + \frac{1}{4.00}\$$right)^{-1}$$ = 2.67\ \Omega$$

Question 7

In a parallel circuit, what is true about the voltage across each resistor?

Accepted Answer

Each resistor has the same voltage across it.

Question 8

A car battery has an emf of 12.0 V and an internal resistance of 0.0100 $$\Omega. $$What is the terminal voltage when the current drawn is 100.0 A?

Accepted Answer

$$V_{	ext{terminal}} = 12.0 - (100.0 	imes 0.0100) = 11.0\ 	ext{V}$$

Question 9

Which configuration is used in household wiring to ensure that each appliance receives the same voltage?

Accepted Answer

Parallel wiring

Question 10

A three-way light bulb contains two filaments rated at 50 W and 100 W. If both filaments are on, what is the total power output?

Accepted Answer

150 W

Question 11

Given a circuit with a 24 V battery and resistors of 110 $$\Omega$$, 180 $$\Omega$$, 220 $$\Omega$$, and 250 $$\Omega$$ arranged as shown in the study materials, what is the equivalent resistance of the circuit?

Accepted Answer

$$R_{eq} = 240\ \Omega$$

Question 12

If a battery with emf $$\mathcal{E}$$ and internal resistance $$r is $$connected to a load resistance $$R$$, what is the expression for the terminal voltage?

Accepted Answer

$$V_{	ext{terminal}} = \mathcal{E} - Ir$$

Question 13

A circuit contains a 6.00 $$\Omega$$ and a 3.00 $$\Omega$$ resistor in series with a 12.0 V battery. What is the voltage across the 6.00 $$\Omega$$ resistor?

Accepted Answer

$$V = IR = 1.33 	imes 6.00 = 8.0\ 	ext{V}$$

Question 14

In a parallel circuit with resistors $$R_1$$ and $$R_2$$, which formula gives the total current supplied by the battery?

Accepted Answer

$$I_{	ext{total}} = I_1$ + I_2$

Question 15

A household circuit is wired in parallel. If one appliance fails, what happens to the other appliances?

Accepted Answer

They continue to operate normally.

Question 16

A car's headlights dim when the starter motor is turned on. Why does this happen?

Accepted Answer

The large current drawn by the starter increases the voltage drop across the internal resistance, reducing terminal voltage.

Question 17

If a resistor is connected to a battery with internal resistance, which equation gives the current in the circuit?

Accepted Answer

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

Question 18

Which of the following is a real-world advantage of parallel wiring in household circuits?

Accepted Answer

Each appliance receives the same voltage and can operate independently.

Lec 7

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