II$.$ Lab multiple choice $(15$ points $-4$ questions$)$

Use the following setup for the next two problems.

In lab A$1$ your team created standing waves in a string with mass per unit length $=k\frac{g}{m}.$ The string was attached at one end to a vibrator which could oscillate with variable frequency, and at the other end it went over a pulley and a weight was hung from the end. The distance between the vibrator and the pulley was $L=1\mathrm{.}5m.$ You decided to alter the mass of the weight, $m,$ and measure the standing wave fundamental frequency, $f,$ while keeping everything else constant. From your results your team created the graph shown below, which includes a straight line fit.

$(3$ pts$)$ Which one of the following statements is correct?

A$.m$ is the independent variable and $f$ is the dependent variable.

B$.m$ is the dependent variable and $f$ is the independent variable.

C$.m$ is the control variable and $f$ is the independent variable.

D$.m$ is the control variable and $f$ is the dependent variable.

E$.$ None of these is correct.

$(4$ pts$)$ From your measurements only, what can you conclude about the relationship between $f$ and $m?$

i$.f$ is consistent with being proportional to $\sqrt[\phantom{2}]{m}.$

ii$.c=\sqrt[\phantom{2}]{\frac{T}{}}$ where $T=mg$

iii. $c=f$ where $=2L$

A$.$ I. only

B$.$ ii$.$ only

C$.$ I. and il$.$

D$.$ ii$.$ and Iii.

E$.$ All of these can be concluded from your measurements.Print UW Net ID $q,$ @uw$.$edu

$(4pts)$ You measure your weight using a household digital scale with a precision of one decimal place. After repeating the measurement three times, you obtained the following data: $150\mathrm{.}6lbs,151\mathrm{.}6lbs,$ and $151\mathrm{.}4$ lbs $.$ How should you report your weight according to the uncertainty analysis procedure used in this course?

A$.151\mathrm{.}20+-0\mathrm{.}05lbs$

B$.151\mathrm{.}2+-0\mathrm{.}53lbs$

C$.151\mathrm{.}2+-0\mathrm{.}05lbs$

D$.151\mathrm{.}2+-0\mathrm{.}1lbs$

E$.151\mathrm{.}2+-0\mathrm{.}5lbs(4$ pts$)$ Light of wavelength $$ is normally incident on a mask with an unknown number of equally spaced narrow slits. Each of the phasor diagrams below corresponds to the same location on a distant screen. The only difference among the three physical situations is the number of slits. Consider the location on the screen where the phasor diagrams above are given. In which case is the intensity of the light at that location the greatest?

A$.$ Case A

B$.$ Case B

C$.$ Case C

D$.$ Two or more cases have equal greatest intensity.

E$.$ More information is needed.