GREPhysics.NET: GR9677 #27

GR9677 #27

Problem

GREPhysics.NET Official Solution

This problem is still being typed.

Lab Methods $\Rightarrow$ }Log Graphs

Log graphs are good for exponential-related phenomenon. Thus (A), (C), and (E) are appropriate, thus eliminated. The stopping potential has a linear relation to the frequency, and thus choice (B) is eliminated. The remaining choice is (D).

Alternate Solutions

Izaac
2012-08-21 01:18:44

One can also simply remember that Bode plots (gain VS $\log\omega$ ) are semilog ones, so obviously D is inappropriate .

Reply to this comment

Comments

Memol
2012-09-18 07:17:56

Can anyone help me with an study reference about these graph stuff?

Reply to this comment

Izaac
2012-08-21 01:18:44

One can also simply remember that Bode plots (gain VS $\log\omega$ ) are semilog ones, so obviously D is inappropriate .

Reply to this comment

keenanman
2007-10-16 12:38:05

In choice D, the graph gain vs 1/frequency is linear. The graph gain vs frequency is hyperbolic.

Reply to this comment

eshaghoulian
2007-10-02 04:11:09

Just to add a little bit as to why log graphs are good for exponential related phenomena, note that a power law in log-log coordinates is a line:

$y=ax^m \Rightarrow log(y) = log(ax^m) = mlog(ax) = mlog(x)+ mlog(a) \Rightarrow log(y) = mlog(x) + mlog(a)$ which is of the form $y = mx+b$ (since $mlog(a)$ is just a constant (like $b$ ) and we identify $y$ with $log(y)$ and $x$ with $log(x)$ , as these are our new axes in log-log coordinates). So the exponent in the power law becomes the slope in log-log coordinates. Testing this is a GRE favorite, as it is a major tool in experimental physics.

tachyon788
2009-10-06 11:48:47

You have a small math error in your use of logs. The equation should be:

$log(y)=log(ax^m)=log(a)+log(x^m)=log(a)+mlog(x)$

Reply to this comment

Post A Comment!

You are replying to:

One can also simply remember that Bode plots (gain VS $\log\omega$ ) are semilog ones, so obviously D is inappropriate .

Bare Basic LaTeX Rosetta Stone
LaTeX syntax supported through dollar sign wrappers $, ex., $\alpha^2_0$ produces $\alpha^2_0$ .
type this...	to get...
$\int_0^\infty$	$\int_0^\infty$
$\partial$	$\partial$
$\Rightarrow$	$\Rightarrow$
$\ddot{x},\dot{x}$	$\ddot{x},\dot{x}$
$\sqrt{z}$	$\sqrt{z}$
$\langle my \rangle$	$\langle my \rangle$
$\left( abacadabra \right)_{me}$	$\left( abacadabra \right)_{me}$
$\vec{E}$	$\vec{E}$
$\frac{a}{b}$	$\frac{a}{b}$

The Sidebar Chatbox...
Scroll to see it, or resize your browser to ignore it...

All-Solutions List | Latest Comments | Unanswered Questions (Cries for Help!) |::| About

This site is not affiliated with ETS, nor is it officially endorsed (yet) by ETS. This site is the work of an individual named Yosun Chang. The solutions, sans user comments and ETS questions, are © 2005 by Yosun Chang except where noted. All rights reserved. / The comments appending particular solutions are due to the respective users. / Educational Testing Service, ETS, the ETS logo, Graduate Record Examinations, and GRE are registered trademarks of Educational Testing Service. The examination questions are © 1997 and © 2001 by ETS.

Bare Basic LaTeX Rosetta Stone