DC Circuits questions - PLEASE HELP! (1 Viewer)

[*~Unique~*]

Hello,

Can someone PLEASE help me with this question ASAP. I would really appreciate it.

Okay. I am doing a practical on DC circuits and am not quite certain about the relationship between temperature and resistance?...If there is an increase in the temperature, is there a decrease in the resistance? Because the particles are more mobile and have more energy, thus enabling them to transfer the charge/energy thingo across a resistor faster?

And another: Are the lamps in a motor car usually connected in series or parallel, and why?
I am not sure, but taking a stab in the dark, are they in parallel because if they were in series they would not be able to individually turn on and off as they do on the dashboard.

Hopefully someone can help me, I have only a few days.

Thankyou.
Kira

 

[hyparzero]

Hello,

Can someone PLEASE help me with this question ASAP. I would really appreciate it.

Okay. I am doing a practical on DC circuits and am not quite certain about the relationship between temperature and resistance?...If there is an increase in the temperature, is there a decrease in the resistance? Because the particles are more mobile and have more energy, thus enabling them to transfer the charge/energy thingo across a resistor faster?

And another: Are the lamps in a motor car usually connected in series or parallel, and why?
I am not sure, but taking a stab in the dark, are they in parallel because if they were in series they would not be able to individually turn on and off as they do on the dashboard.

Hopefully someone can help me, I have only a few days.

Thankyou.
Kira

For metal conductors, resistance increases as temperature in increases. This is because the atomic structure of the conductor starts to vibrate erratically, disrupting the flow of electrons - hence an increase in resistivity.

That is why superconductors (almost zero resistance) only operate at extremely cold temperatures of - 250*C or less. High temperatures will not aid the flow of electrons, only inhibit their movement. (the opposite is true for semi-conductors)

I don't really understand your second question, do you mean the headlamps or the blinkers?

The headlamps of any car is always connected in parallel, first of all, its for safety reasons. Imagine if one headlamp was to burn out, the other wouldn't work if it was connected in series - becauses there is a disruption in the series circuit. A parallel connect would solve this problem.

Blinkers are connected separately to one another, so doesnt make any difference.

 

[*~Unique~*]

thanks for the help. i really appreciate it.
i wasnt too sure about the second question either, but that is exactly the way it came.
your answer should be sufficient, lol. jj! it is pretty much what they ask for anyway - it is still to do with motor cars.
so...thanks!