!"#4,%( %%&'()**+! &#
7#89-"(1%%"%%8"':(;#:"4#-%(<(=%%>"(?(<(@,:&A"(BC?D(E(!"#%&'()*>,#:4&'(.484:"*(BC?D Turn over
PMT
!"! "#!#!%&'%()*%#+!+,!-%+%(*)#%!+.%!/.(0#!%1%/+(,#2!#%0+)3(0%-!,)1!-(,'5!(11,6%-!+,!711!8(111!'1+(+!-)5+#/%!!9
! :!',+%#+)1!-)77%(%#/%!;'9-9′′1)/(,55!+.%!'1
+0(*!5.,65!,#%!,)1!-(,'!
8%+6%%#!+.%!'1+%59
!
(cid:58)hen the p.d. is 0 V the oil drop accelerates to ter(cid:80)inal (cid:89)elocit(cid:92). (cid:55)he p.d. is increased.
"+!)5!,85%(3%-!+.
+!+!
!′(+)/>1
(!′9−9!"!+.11)#0!#-!(%*)#5!5++),#(4!
8%+6%%#!+.%!'1
+!?;