Warning: foreach() argument must be of type array|object, bool given in /var/www/html/web/app/themes/studypress-core-theme/template-parts/header/mobile-offcanvas.php on line 20

The power rating of a light bulb (such as a 100-W bulb) is the power it dissipates when connected across a 120-V potential difference. What is the resistance of (a) a 100-W bulb and (b) a 60-W bulb? (c) How much current does each bulb draw in normal use?

Short Answer

Expert verified
  1. The resistance of 100-W bulb is144Ω.
  2. The resistance of 60-W bulb is 240Ω.
  3. The current drawn by each bulb is 0.833 A and 0.500 A.

Step by step solution

01

Determination of the resistance of 100-W and 60-W bulbs.

The connection of the bulb is across a 120-V potential difference.

The expression of power is,

P=V2R

Solve for R and 100 W bulb,

role="math" localid="1655719758468" R=V2P=(120V)2(100W)=144Ω

Repeat the calculation for 60 W bulb,

R=V2P=(120V)2(60W)=240ΩThus,theresistancesfor100-Wbulbisandfor60Wbulbis144Ωandfor60Wbulbis240Ω

02

(b) Determination of the current drawn by each bulb is

Use the Ohm’s Law

V=lRl=VRForthe100Wbulb:l=(120V)(144Ω)=0.833AForthe60Wbulb:l=(120V)(240Ω)=0.500AThus,thecurrentdrawnby100-Wbulbandthe60-Wbulbis0.833Aand0.500A

Unlock Step-by-Step Solutions & Ace Your Exams!

  • Full Textbook Solutions

    Get detailed explanations and key concepts

  • Unlimited Al creation

    Al flashcards, explanations, exams and more...

  • Ads-free access

    To over 500 millions flashcards

  • Money-back guarantee

    We refund you if you fail your exam.

Over 30 million students worldwide already upgrade their learning with Vaia!

One App. One Place for Learning.

All the tools & learning materials you need for study success - in one app.

Get started for free

Most popular questions from this chapter

A resistor with resistance Ris connected to a battery that has emf 12.0 V and internal resistance r=0.40Ω. For what two values of R will the power dissipated in the resistor be 80.0 W ?

Two coils have mutual inductance M=3.25×10-4H. The current in the first coil increases at a uniform rate of 830 A/S. (a) what is the magnitude of the induced emf in the second coil? Is it constant? (b) Suppose that the current described is in the second coil rather than the first. What is the magnitude of the induced emf in the first coil?

In Europe the standard voltage in homes is 220 V instead of the 120 used in the United States. Therefore a “100-W” European bulb would be intended for use with a 220-V potential difference (see Problem 25.36). (a) If you bring a “100-W” European bulb home to the United States, what should be its U.S. power rating? (b) How much current will the 100-W European bulb draw in normal use in the United States?

(a) What is the potential difference Vadin the circuit of Fig. P25.62? (b) What is the terminal voltage of the 4.00-Vbattery? (c) A battery with emf and internal resistance 0.50Ωis inserted in the circuit at d, with its negative terminal connected to the negative terminal of the 8.00-Vbattery. What is the difference of potential Vbcbetween the terminals of the 4.00-Vbattery now?

Questions: A conductor that carries a net charge has a hollow, empty cavity in its interior. Does the potential vary from point to point within the material of the conductor? What about within the cavity? How does the potential inside the cavity compare to the potential within the material of the conductor?

See all solutions

Recommended explanations on Physics Textbooks

View all explanations

What do you think about this solution?

We value your feedback to improve our textbook solutions.

Study anywhere. Anytime. Across all devices.

Sign-up for free