What Happens When a Person Touches a Live Wire?

  • Thread starter Thread starter Tcat
  • Start date Start date
  • Tags Tags
    Body Resistance
AI Thread Summary
When a person with a resistance of 13.0 kiloohms touches a live wire with a power supply of 16.0 V and an internal resistance of 2100 ohms, the current through their body can be calculated using the formula I = V/(R_p + R_i), resulting in a current of 1.06×10−3 A. For power dissipation, the correct approach involves determining the voltage drop across the person's body rather than using the total voltage of the circuit. The initial calculation of power using P = I*V is incorrect because it applies the full voltage instead of the voltage drop across the individual’s resistance. The discussion highlights the importance of correctly identifying the voltage relevant to the specific part of the circuit. Understanding these principles is crucial for accurately assessing electrical safety and effects on the human body.
Tcat
Messages
28
Reaction score
0
Suppose that a person has a resistance of 13.0 kiloohms as part of a circuit which passes through his hands. This person accidentally grasps the terminals of a power supply with a potential difference of 16.0 V.
PART A:If the internal resistance of the power supply is 2100 ohms , what is the current through the person's body?
I calculated the current to be 1.06×10−3 A by using the equation I = V/(R_p + R_i)
PART B: To find the power dissipated in his body I thought you use the equation P = I*V so P =(1.06*10^-3 A)*(16.0V) which gave me 1.70*10^-2 which is wrong. What I am doing wrong??
Thank you for your help
 
Physics news on Phys.org
I think V isn't 16 V, since you want the voltage drop across his body, not the whole circuit
 

Thread 'Errors and significant figures'

I multiplied the values first without the error limit. Got 19.38. rounded it off to 2 significant figures since the given data has 2 significant figures. So = 19. For error I used the above formula. It comes out about 1.48. Now my question is. Should I write the answer as 19±1.5 (rounding 1.48 to 2 significant figures) OR should I write it as 19±1. So in short, should the error have same number of significant figures as the mean value or should it have the same number of decimal places as...
View full post »
Thread 'A cylinder connected to a hanging mass'

Thread 'A cylinder connected to a hanging mass'

Let's declare that for the cylinder, mass = M = 10 kg Radius = R = 4 m For the wall and the floor, Friction coeff = ##\mu## = 0.5 For the hanging mass, mass = m = 11 kg First, we divide the force according to their respective plane (x and y thing, correct me if I'm wrong) and according to which, cylinder or the hanging mass, they're working on. Force on the hanging mass $$mg - T = ma$$ Force(Cylinder) on y $$N_f + f_w - Mg = 0$$ Force(Cylinder) on x $$T + f_f - N_w = Ma$$ There's also...
View full post »

Similar threads

Power Math: Finding Current & Power Dissipated through Person
Replies
1
Views
2K
Resistance, current and current density
Replies
8
Views
2K
Power and Resistance in Electrical Circuits
Replies
2
Views
2K
Internal resistance of each cell+energy dissipated in 1 min
Replies
20
Views
5K
Electric Potential across charging battery.
Replies
5
Views
2K
Recharging a battery when Lightbulb and TV are in parallel
Replies
3
Views
1K
Electric Power - Which formula to use and when?
Replies
6
Views
1K
What Is the Current Flow and Resistance in Series-Connected Bulbs?
Replies
18
Views
4K
Coils arrangement so the hotplate operates at 3 diff. powers
Replies
25
Views
3K
Reading Voltmeters: Constant Terminal Voltages & Resistances
Replies
13
Views
3K

Hot Threads

Recent Insights

Back
Top