Sunday

April 19, 2015

April 19, 2015

Posted by **ash** on Thursday, October 25, 2007 at 11:22pm.

During a lie dector test, a voltage of 6 V is impressed across two fingers. When a certain question is asked, the resistance between the fingers drops from 400,000 ohms to 200, 000 ohms. What is the current (a) initially through the fingers, and (b) when the resistance between them drops? (this question I dont understand)

How much resistance allows an impressed voltage of 6V to produce a current of 0.006 A ? I got 1000 ohm

What is the resistance of a clothes iron that draws a current of 12 A at 120 V? I got 10 ohm

The current in an incandescent lamp is 0.5A when connected to a 120-V circuit, and 0.2A when connected to a 10-V source. Does the resistance of the lamp change in these cases? Explain your answers and defend it with numerical values?( I got: 120 V/0.5A=240 ohms and 10V/0.2A=50 ohms. Yes the resistance changes in both cases.)

- ap physics -
**drwls**, Thursday, October 25, 2007 at 11:31pmThe current in the first problem is V/R in both cases. Just compute the numbers at bot values of R.

Your second answer is correct.

Your third answer is correct.

Yes, the resistance of the tungsten lamp filament increases quite a bit when it gets hotter (as it does with higher voltage operation).

ap physics - can you please check my answers and help me with one question? ...

Physics - Would someone please check my answers? thanks During a lie detector ...

Physics;Help!!!!!! - There is apparently no one online who can help with physics...

Test-Taking Strategies - Please check my answers! Please Check if they are wrong...

TO MS SUE - Please check my answers to my question, I posted this question ...

PHYSICS PLS HELP - Internal resistance problem. Suppose that in Figure 3.3, Vo=...

Physical Science: Series Circuit - There is a circuit of 2 lamps in a series. If...

PHYSICS 1A - how much current is drawn by a lamp that has a resistance of 1.2 O ...

Hector >> history - I've deleted your 28-question test. You posted no ...

Physics - A 22-ohm resistor and a 33-ohm resistor are connected in series and ...