Please answer every question! Circuit a has a battery connected in a circuit wit
ID: 1873212 • Letter: P
Question
Please answer every question!
Circuit a has a battery connected in a circuit with four identical light bulbs (numbered 1 through 4) and three switches (lettered A through C). The switches are shown in their open positions. The battery is ideal—it has no resistance of its own. We will also assume that the resistance of each bulb is the same no matter how much current passes through it. Circuit b is exactly the same as circuit a, except that a fifth light bulb, identical to the other four, has been added to the circuit.
(a) In Circuit a, if you want to maximize the brightness of bulb 4, what should you do with the switches? (Select all that apply.)
Switch A should be open.
Switch A should be closed.
Switch A doesn't matter—having it open or closed has no effect on bulb 4.
Switch B should be open.
Switch B should be closed.
Switch B doesn't matter—having it open or closed has no effect on bulb 4.
Switch C should be open.
Switch C should be closed.
Switch C doesn't matter—having it open or closed has no effect on bulb 4.
(b) In Circuit b, if you want to maximize the brightness of bulb 4, what should you do with the switches? (Select all that apply.)
Switch A should be open.
Switch A should be closed.
Switch A doesn't matter—having it open or closed has no effect on bulb 4.
Switch B should be open.
Switch B should be closed.
Switch B doesn't matter—having it open or closed has no effect on bulb 4.
Switch C should be open.
Switch C should be closed.
Switch C doesn't matter—having it open or closed has no effect on bulb 4.
(c) In Circuit b, you close all the switches. Rank the bulbs in circuit b by their brightness, from brightest to dimmest, with all the switches closed. (Use only ">" or "=" symbols. Do not include any parentheses around the letters or symbols.)
(d) Starting with all the switches closed in Circuit b, you then open switch B. When you open switch B, what happens to bulbs 3, 4, and 5? (Select all that apply.)
Bulb 3 gets brighter.
Bulb 3 gets dimmer.
Bulb 3 stays the same.
Bulb 4 gets brighter.
Bulb 4 gets dimmer.
Bulb 4 stays the same.
Bulb 5 gets brighter.
Bulb 5 gets dimmer.
Bulb 5 stays the same.
(e) Now, all the switches are closed in both circuits. Which of the following statements are true when all switches are closed? (Select all that apply.)
Bulb 2 in Circuit a is brighter than Bulb 2 in Circuit b.
Bulb 3 in Circuit a is brighter than Bulb 3 in Circuit b.
Bulb 2 in Circuit b is the same brightness as Bulb 5 in Circuit b.
Circuit a has more power dissipated in it than does Circuit b.
The current through the battery in Circuit a is larger than the current through the battery in Circuit b.
The current through Bulb 2 in Circuit a is larger than the current through Bulb 2 in Circuit b.
The potential difference across Bulb 4 in Circuit a is larger than the potential difference across Bulb 4 in Circuit b.
For the rest of this problem, use these numbers. The battery voltage is 18.0 V, and the resistance of each light bulb is 2.00 ohms. For convenience, the circuit diagrams are shown again here, too, with the switches set as in the questions below.
(f) In Circuit b, with switch A open and switches B and C both closed, calculate the equivalent resistance of the circuit.
(g) In Circuit b, with switch A open and switches B and C both closed, calculate the magnitude of the current in bulb 4.
A
(h) In Circuit b, with switch A open and switches B and C both closed, calculate the magnitude of the potential difference across bulb 5.
V
(i) Now, we consider Circuit a. In Circuit a, with switch A open and switches B and C both closed, calculate the equivalent resistance of the circuit.
(j) In Circuit a, with switch A open and switches B and C both closed, calculate the power dissipated in Bulb 1.
W
Explanation / Answer
a) The correct options are Switch A doesn't matter—having it open or closed has no effect on bulb 4, Switch B doesn't matter—having it open or closed has no effect on bulb 4 and Switch C should be closed because as per the power equation, the brightness increases if either the current through the bulb or voltage across it increases.
b) Switch A doesn't matter—having it open or closed has no effect on bulb 4, Switch B should be open and Switch C should be closed because to make the current flow through bulb , switch C must be closed and when switch B is open the voltage between bulb 4 and bulb 5 is divided.
c) If we close all the switched bulb 1 and switch A are in parallel which makes bulb 1 ineffective. All the voltage goes to bulb 2 and the voltages across bulb 3 and 4 are same which is v/3 and voltage across bulb 5 is 2*v/3. Therefore, order of brightness will be 2>5>4=3>1
d) Bulb 3 gets dimmer, Bulb 5 gets dimmer and Bulb 4 gets brighter. The voltage across bulb 5 will go down as switch is opened and for bulb 4, the voltage will go up.
e) Bulb 3 in Circuit a is brighter than Bulb 3 in Circuit b since the potential difference acros bulb 3 in circuit a is greater than voltage difference as in circuit b. ,
Circuit a has more power dissipated in it than does Circuit b, just calculste the power dissipated in each circuit.
The current through the battery in Circuit a is larger than the current through the battery in Circuit b because current in circuit a is 3v^2/R and circuit b is 5v^2/3R
The potential difference across Bulb 4 in Circuit a is larger than the potential difference across Bulb 4 in Circuit b.
Next parts are really easy, just use series and parallel resistances formulas