Register to reply 
Finding power consumed by an electric razor 
Share this thread: 
#1
Feb809, 03:26 PM

P: 2

A tourist takes his 21 W, 120 V AC razor to Europe, finds a special adapter, and plugs it into 220 V AC. What power does the razor consume as it goes up in smoke?
P=IV=deltaVsquared/R attempt at solution: I used P=IV for 120 V to find the current, and using that number, plugged the numbers into the equation for 220V. The hint for the problem says that the resistance doesn't change for the razor in Europe... but I don't know how that helps. I feel like I'm missing something very easy but I'm stuck. 


#2
Feb809, 03:45 PM

Mentor
P: 40,658

Welcome to the PF. The key here is that the resistance doesn't change. I don't think you want to write:
[tex]P = \frac{\Delta {V^2}}{R}[/tex] Instead, write two equations, one for the US and one for smokey Europe... 


#3
Feb809, 04:36 PM

P: 2

Oh man that was easy.. I'm a little embarrassed. Thanks for the help!



#4
Feb1009, 09:16 PM

P: 1

Finding power consumed by an electric razor
Hey seems like you guys figured it out. Can you help me. I'm stuck on the same question and I don't know what to do.



Register to reply 
Related Discussions  
Energy consumed to create force  Classical Physics  8  
Power in / power out for electric motor  Engineering Systems & Design  7  
Least fuel consumed from point A to B with no time constraint  Mechanical Engineering  7  
What would happen if I were to near and be consumed by a black hole?  Astronomy & Astrophysics  1  
100 Calories consumed/mile?  General Physics  3 