Which of the following statements explain why the two-source interference equations are not valid for an observer far away from two red LED signal lights? 1. not monochromatic sources
2. incoherent sources
3. observed from a distance similar to or smaller than the separation between the sources

a. 1 only
b. 2 only
c. 3 only
d. 1 and 2 only
e. 1 and 3 only
f. 2 and 3 only
g. all three

  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

b. lifting dumbbell weight at 20-degree angle from the body after a 45-degree angle