Textbook Question
Draw a circuit diagram for the circuit of FIGURE EX28.2.
2
views
Ch 28: Fundamentals of Circuits
Knight Calc5th EditionPhysics for Scientists and EngineersISBN: 9780137344796
Not the one you use?Change textbookSelect a different textbook
Table of contents
- Ch 01: Concepts of Motion35
- Ch 02: Kinematics in One Dimension75
- Ch 03: Vectors and Coordinate Systems58
- Ch 04: Kinematics in Two Dimensions60
- Ch 05: Force and Motion23
- Ch 06: Dynamics I: Motion Along a Line53
- Ch 07: Newton's Third Law27
- Ch 08: Dynamics II: Motion in a Plane52
- Ch 09: Work and Kinetic Energy56
- Ch 10: Interactions and Potential Energy50
- Ch 11: Impulse and Momentum56
- Ch 12: Rotation of a Rigid Body71
- Ch 13: Newton's Theory of Gravity52
- Ch 14: Fluids and Elasticity44
- Ch 15: Oscillations55
- Ch 16: Traveling Waves37
- Ch 17: Superposition39
- Ch 18: A Macroscopic Description of Matter53
- Ch 19: Work, Heat, and the First Law of Thermodynamics60
- Ch 20: The Micro/Macro Connection53
- Ch 21: Heat Engines and Refrigerators34
- Ch 22: Electric Charges and Forces40
- Ch 23: The Electric Field39
- Ch 24: Gauss' Law32
- Ch 25: The Electric Potential63
- Ch 26: Potential and Field57
- Ch 27: Current and Resistance42
- Ch 28: Fundamentals of Circuits39
- Ch 29: The Magnetic Field47
- Ch 30: Electromagnetic Induction60
- Ch 31: Electromagnetic Fields and Waves32
- Ch 32: AC Circuits63
- Ch 33: Wave Optics32
- Ch 34: Ray Optics57
- Ch 35: Optical Instruments30
- Ch 36: Special Relativity38
- Ch 37: The Foundations of Modern Physics25
- Ch 38: Quantization49
- Ch 39: Wave Functions and Uncertainty31
- Ch 40: One-Dimensional Quantum Mechanics35
- Ch 41: Atomic Physics18
- Ch 42: Nuclear Physics27
Knight Calc5th EditionPhysics for Scientists and EngineersISBN: 9780137344796Not the one you use?Change textbook
Chapter 28, Problem 9a
A 60 W lightbulb and a 100 W lightbulb are placed in the circuit shown in FIGURE EX28.9. Both bulbs are glowing. Which bulb is brighter? Or are they equally bright?
Verified step by step guidance1
Step 1: Understand the relationship between power, voltage, and resistance. The power of a bulb is given by the formula: , where is the voltage across the bulb and is the resistance of the bulb.
Step 2: Recall that the resistance of a bulb can be calculated using the formula: . Since the power ratings of the bulbs are given (60 W and 100 W), their resistances can be compared. The bulb with lower power rating will have higher resistance.
Step 3: Analyze the circuit configuration. If the bulbs are connected in series, the current through both bulbs will be the same. In this case, the bulb with higher resistance (60 W bulb) will have a larger voltage drop across it, making it brighter. If the bulbs are connected in parallel, the voltage across both bulbs will be the same, and the bulb with higher power rating (100 W bulb) will be brighter.
Step 4: Determine the circuit type based on the problem context or diagram (FIGURE EX28.9). If the bulbs are in series, brightness depends on resistance; if in parallel, brightness depends on power rating.
Step 5: Conclude which bulb is brighter based on the circuit type. For series circuits, the 60 W bulb is brighter due to higher resistance. For parallel circuits, the 100 W bulb is brighter due to higher power rating.
Verified video answer for a similar problem:
This video solution was recommended by our tutors as helpful for the problem above.
Video duration:
2mWas this helpful?
Key Concepts
Here are the essential concepts you must grasp in order to answer the question correctly.
Power Rating
The power rating of a lightbulb, measured in watts (W), indicates the rate at which it converts electrical energy into light and heat. A higher wattage means the bulb consumes more energy and typically produces more light. In this case, the 100 W bulb is designed to emit more light than the 60 W bulb when both are operating under the same voltage.
Recommended video:
Guided course
06:00
Power
Brightness Perception
Brightness perception is influenced by the amount of light emitted by a bulb and how our eyes perceive that light. The human eye responds logarithmically to light intensity, meaning that a bulb with a higher power rating will generally appear brighter. Therefore, the 100 W bulb will appear brighter than the 60 W bulb due to its higher light output.
Recommended video:
Guided course
12:00Young's Double Slit Experiment
Circuit Configuration
The configuration of the circuit affects how voltage and current are distributed among the components. If the bulbs are connected in series, they share the same current, which can affect their brightness. In a parallel configuration, each bulb receives the full voltage, allowing the 100 W bulb to shine brighter than the 60 W bulb, confirming that the power rating directly influences brightness.
Recommended video:
Guided course
09:40LRC Circuits
Related Practice
Textbook Question
Draw a graph of the potential as a function of the distance traveled through the circuit, traveling cw from V = 0 V at the lower left corner.
2
views
Textbook Question
Draw a circuit diagram for the circuit of FIGURE EX28.1.
1
views
Textbook Question
A typical American family uses 1000 kWh of electricity a month. What is the average current in the 120 V power line to the house?
1
views
Textbook Question
The five identical bulbs in FIGURE EX28.11 are all glowing. The battery is ideal. What is the order of brightness of the bulbs, from brightest to dimmest? Some may be equal.
1
views
Textbook Question
A 100 W (120 V) incandescent lightbulb contains a 7.0-cm-long tungsten filament. The high-temperature resistivity of tungsten is 9.0 x 10⁻⁷ Ωm. What is the diameter of the filament?
1
views