AP Tests and solutions

The good news is that several of you got high or perfect scores on the refraction problem.  Unfortunately that is all the good news.  

Adding a weight on top of a piston adds to the original pressure and compresses the gas. If the gas cylinder is in a water bath of fixed temperature, the gas temperature does not change appreciably, i.e. the processes are isothermal. Since T doesn't change then PxV is constant so 

Vnew = Vold x (Pold/Pnew). 

If the pressure, P, is held constant during a process, its isobaric and since PV = nRT and n and R didn't change  we have 1= Vnew x P /(nrTnew) = Vold x P /(nRTold). Canceling  n and R, multiplying by Tenw and cancelling the Ps which are equal in isobaric processes, we get 

Vnew  = Vold x (Tnew/Told)

No one seems to know how to use a volt meter despite having taken over 100 measurements with voltmeters. [You do not insert voltmeters in series with circuit elements. They measure the voltage difference across an element, i.e. the potential difference ( also known as the voltage difference)  between two different points in a circuit.]

Some of you seem to think that a single deuterium nucleus has a mass of 2 kg. An atomic mass unit is 1.66E-27 kg not 1 kg. Most of you never got that far.  

Here are somewhat rough  solutions for all of FR 2001. We will go over MC 1 in class tomorrow.

FR2001Solns.PDF