Hi everyone I'm stuck with a few questions hopefully I can get some assistance. 1) A student repeating Millikan's oil drop experiment to measure electronic charge used an incorrectly calibrated voltmeter and obtained the following values for charges on the drops: Charges on drop / 10^-19C 3.9 7.8 9.1 5.2 Using these results what value should he take for the electronic charge, in C? 2) If one of the slits of the standard Young's double slit demonstration of interference in light is painted over so that it only transmit only half the light intensity, why does the dark lines increase in density and bright lines decrease in density? 3) One junction of X of a thermocouple is placed in melting ice at 273K and the other junction Y in steam at 373K. The e.m.f measured is 1.0mV. Now Y is transferred to a bath whose temp is 398K. Assume variation of e.m.f with temp diff is linear, the e.m.f recored will be? 4) See the attachment. The resistance between A and C is 8ohm. What is resistance R? For 1, I know charges exist in multiples that they are discrete. I assumed all the values given to be from a drop since they stated on oil drop. How then can I find the charge? For 2, I know bright lines will decrease in intensity as at the bright lines, the total intensity is lower compared to 2 equal intense waves constructive interfering. But why does the dark fringe increase in intensity? Does it mean it becomes darker? Why so? 3) 1.0mV = k(373-273) E = k(398-273) Solving, I get the value of E to be 0.125. Answer given was 1.25. 4) I don't know how to start at all. Using kirchoff's law doesn't seem to provide anything. Any advice? Answer 4ohms. Sorry for the long post hope someone could lend a helping hand! thanks!