1answer.
Ask question
Login Signup
Ask question
All categories
  • English
  • Mathematics
  • Social Studies
  • Business
  • History
  • Health
  • Geography
  • Biology
  • Physics
  • Chemistry
  • Computers and Technology
  • Arts
  • World Languages
  • Spanish
  • French
  • German
  • Advanced Placement (AP)
  • SAT
  • Medicine
  • Law
  • Engineering
IRISSAK [1]
2 years ago
5

In Europe the standard voltage in homes is 220 V instead of the 120 V used in the United States. Therefore "100-W" European bulb

would be intended for use with a 220-V potential difference. (a) If you bring a "100-W" European bulb home to the untied States, what should be its US power rating? (b) How much current will the 100-W European bulb draw in normal use in the United States?
Physics
1 answer:
Elena L [17]2 years ago
5 0

One very handy dandy formula for electrical power used by a device is

Power = (voltage)² / (resistance)

I can see <em>two</em> ways to solve the problem using this formula.

<u>Way #1:</u>

We know the bulb uses 100 watts when goosed with 220V.  What is the bulb's resistance ?

Power = (voltage)² / (resistance)

100 w = (220v)² / R

Divide each side by (220v)² :

1/R = (100w) / (220v)²

Take the reciprocal of each side:

R = (220v)²/(100w)

R = 484 ohms

OK. Now plug the bulb into 120 volts:

Power = (voltage)² / (resistance)

Power = (120v)² / (484 ohms)

<em>Power = 29.75 watts</em>

and

Current = (voltage) / (resistance)

Current = (120v) / (484 ohms)

<em>Current = 0.248 Ampere</em>

===================================

<u>Way #2:</u>

Power = (voltage)² / (resistance)

Just look at that formula for a second.  It says that the power used is proportional to the (voltage) SQUARED.  This may be all the information we really need.

Reduce the voltage from 220v to 120v, the power used by the bulb will be reduced to

(120/220)²  = (0.5454)²  =  0.2975 of the original power  

And there you go.  0.2975 of the original 100w is <em>29.75 watts.</em>

And finally, using Way #2:

Power = (voltage) x (current)

29.75w = (120v) x (current)

Current = (29.75 / 120) (w/v)

<em>Current = 0.248 Ampere</em>

Isn't it great how it doesn't matter whether you use Way-#1 or Way-#2, you get the same answers either way ! ? !  That tells you two things: -- Both ways to find the answers are probably reliable.  -- The answers are probably correct.

You're a good bot.  Go tell your masters that you successfully tricked a Brainly Ace into spending a half hour of his time on your purposeless question.

You might be interested in
All moving objects don’t have momentum<br> A. True<br> B. False
mestny [16]

Answer:

No

Explanation:

Some objects gain momentum.

4 0
2 years ago
Read 2 more answers
Explain relative velocity.
xxTIMURxx [149]

Answer:

The relative velocity of an object A with respect to another object B.

Explanation:

The relative velocity of an object A with respect to another object B is the velocity that object A would appear to have to an observer situated on object B moving along with it.

4 0
3 years ago
Most energy obtained from water is converted from _____.
Snowcat [4.5K]
Potential energy behind dams
7 0
3 years ago
Read 2 more answers
A stuntman jumps from the roof of a building to the safety net below. How far has the stuntman fallen after 1.6 seconds?
Fantom [35]
How tall is the building?
u need to divide the height by 1.6 to get your answer
6 0
3 years ago
What is the equivalent unit to a newton?​
allsm [11]
My science teacher said that there is no equivalent unit to a newton
6 0
3 years ago
Read 2 more answers
Other questions:
  • The peak intensity of radiation from Star Beta is 350 nm. In what spectral band is this? UV, radio waves, visible light, or infa
    10·2 answers
  • Question 7 Unsaved Brycen can cover half a basketball court (about 14 meters) in 4.0 seconds flat! How fast can he run? Question
    11·1 answer
  • What are some types of landforms on Earth’s surface?<br><br><br><br> PLS ANSWER QUICK 11 POINTS
    7·2 answers
  • How do I disable internal laptop display on Linux? So that I can project to external monitor! video=LVDS-1:d and video=eDP-1:d w
    8·1 answer
  • The mass of the basketball shown below is 4 times the mass of the baseball.
    5·1 answer
  • would it be possible for a small man running fast to have the same kinetic energy as a large man who runs slowly?
    8·1 answer
  • What is the entropy of a closed system in which 28 distinguishable grains of sand are distributed among 1000 distinguishable equ
    10·1 answer
  • Necesito ayuda urgente por favor, gracias 2) Sabiendo que el espacio que recorre un cuerpo en función del tiempo viene dado por
    12·1 answer
  • What year did Badminton become a full-medal Olympic sport?
    6·1 answer
  • It is class 12th physics questions can anyone help me ​
    10·1 answer
Add answer
Login
Not registered? Fast signup
Signup
Login Signup
Ask question!