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Current and Circuits Unit

PROGRESSIVE SCIENCE INITIATIVE® (PSI®)

6 Comments

Siu Jia Wong • 2 years, 11 months agologin to reply

Dear admin, would you please check again the answer of Homework > MCQ > Q6 (Graph of P vs R)? Thank you!

Melissa Axelsson • 2 years, 11 months agologin to reply

The question is asking about the resistivity of the wire (the greek letter rho). Perhaps you thought it was P for power? As the temperature of a metal increases, its atoms vibrate more and provide more of a resistance to current flow. So resistivity increases linearly, choice b. Please see slides 16 and 17 of the notebook presentation for the explanation. Thanks, John

John Ennis • 2 years, 11 months agologin to reply

The question is asking about the resistivity of the wire (the greek letter rho). Perhaps you thought it was P for power? As the temperature of a metal increases, its atoms vibrate more and provide more of a resistance to current flow. So resistivity increases linearly, choice b. Please see slides 16 and 17 of the notebook presentation for the explanation. Thanks, John

Siu Jia Wong • 2 years, 11 months agologin to reply

Dear John and Melissa, thank you for your reply. I am sorry that I point the wrong question. The question that I want to ask is Q18 (Graph of P vs R). So sorry for this huge mistake.

Siu Jia Wong • 2 years, 11 months agologin to reply

The answer has no problem for Q18. Thank you so much for your help!

John Ennis • 2 years, 11 months agologin to reply

I think we're ok with the answer. Answer (D) has a graph of P versus R. For P = V^2/R. Since V is constant, P is a function of 1/R. Graph (D) shows a 1/R function - large as R approaches zero, and approaching zero as R increases. Does this help?

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