Answer the following questions related to ex. 35.1 and effective focal length: (a) redo example 35.1, but this time with the two lenses separated by 10mm rather than 60mm. you should still assume that a 10-cm-tall object is 500 mm from the first lens. what is the effective focal length of this double-lens system? (b) prove the following statement: if the distance separating two lenses is zero, then the effective local length of the system is f, where 1 f = 1 f1 + 1 f2 to prove this, basically redo the same problem as part a, but don’t plug in numbers. 2. suppose you have a picture that is very underexposed (too dark). how would you improve the image under the following conditions? (a) you are allowed to change the focal length, but not the aperture size nor shutter speed. (b) you are allowed to change the aperture size, but not the focal length nor shutter speed. (c) you are allowed to change the shutter speed, but not the focal length nor aperture size. (d) what happens to the magnification of the picture in each of the three cases above?

Acetic acid  /əˈsiːtɪk/, systematically named  ethanoic acid  /ˌɛθəˈnoʊɪk/, is a colourless liquid  organic compound  with the  chemical formula  ch3cooh (also written as ch3co2h or c2h4o2). when undiluted, it is sometimes called  glacial acetic acid.  vinegar  is no less than 4% acetic acid by volume, making acetic acid the main component of vinegar apart from water. acetic acid has a distinctive sour taste and pungent smell. in addition to household vinegar, it is mainly produced as a precursor to  polyvinyl acetate  and  cellulose acetate. it is classified as a  weak acid  since it only partially  dissociates  in solution, but concentrated acetic acid is corrosive and can attack the skin.acetic acidnamespreferred iupac nameacetic acidsystematic iupac nameethanoic acidother namesvinegar (when dilute); hydrogen acetate; methanecarboxylic acid[1][2]identifierscas number64-19-7  3d model (jsmol)interactive image3dmetb00009 reference506007chebichebi: 15366  chemblchembl539  chemspider171  drugbankdb03166  echa infocard100.000.528ec number200-580-7e numbere260  (preservatives)gmelin reference1380iuphar/bps1058keggd00010  meshacetic+acidpubchem  cid176rtecs numberaf1225000uniiq40q9n063p  un number2789inchiinchi=1s/c2h4o2/c1-2(3)4/h1h3,(h,3,4)  key:   qtbsbxvteameqo-uhfffaoysa-n  smilescc(o)=o

Gotta have a picture ^^