1) An oil drop of mass 4.92 x 10-15 kg is balanced between two large, horizontal parallel plates 4.3 cm wide, 7.2 cm long and 1.2 cm apart, maintained at a potential difference of 510.4 V. a) Draw a neat fully labelled diagram of the problem including forces, charges and distances.

b) How many elementary charges does the electron have?

c) Explain clearly to a Grade 9 student how Millikan was able to use an apparatus like this to determine that charge is always an integral multiple of an elementary charge.

answer: cesare beccaria developed the classical school of criminology with from philosopher jeremy bentham

explanation:

  the grams     of oxygen gas   that can be produced     is 20.6   grams of o₂

calculation

2liclo₃ →   2 licl + 3 o₂

step 1:   find the moles of liclo₃

moles = mass÷ molar mass

from periodic table the molar mass of liclo₃ =6.9 +35.5   +(16 x3) =90.4 g/mol

moles=38.7 g÷90.4 g/mol=0.4281   moles

step 2:   use the   mole ratio   to calculate the moles of o2

from equation above, liclo₃: o₂   is 2: 3  

therefore the moles of   o₂=0.4281 moles x3/2 =0.6422   moles

step 3: find mass   of o₂

mass= moles x molar mass

from periodic table the   molar mass of   o₂ = 16 x2= 32 g/mol

mass=0.6422   moles   x   32 g/mol = 20.6 grams of o₂

force is mass*acceleration.

we have a very small mass: 11.4*0.001 kg

if we want 0.035n of force, we need an acceleration:

0.035 = 11.4*0.001*a

a = 0.035/(11.4*0.001) m/s^2

what is the speed of a softball that travels 20m in 2secs

speed = 20/2 = 10 m/s