Constructive interference occurs when waves meet.
a. trough to crest and crest to trough
b. crest to trough and crest to trough
c. trough to crest and trough to crest
d. crest to crest and trough to trough

Constructive interference occurs when the crest of one wave meets the crest of another wave and hence, a higher amplitude wave is formed.

Option D

Explanation:

According to the superposition principle, a constructive interference occurs when more than two waves of same kind meets at the same points, then the resultant wave amplitudes are equal to vector sums of the amplitude of all the individual waves.

When crest of a wave meets the crests of another wave, or likewise, the trough or a wave meets the trough of other wave, a higher amplitude wave is formed which is known as a constructive wave. And, when a crest of a wave reaches the trough, a lower amplitude wave is formed which is known as destructive wave.

  1.the balanced   chemical equation is as below

cu +   2 ag(no)₃ → cu(no₃)₂   +2 ag

2.the   much silver   produced   is   50.9 g

step 1: find the   moles of cu

moles =   mass÷   molar mass

  from periodic table the molar mass of cu = 63.5 g/mol

moles is therefore = 15.00 g÷ 63.5 g/mol = 0.236   moles

step 2: use the mole ratio to determine the   moles of ag

from equation above   cu: ag   is 1: 2

therefore the moles of ag   =0.236   moles   x 2/1 =0.472   moles

step 3: find the mass   of ag

mass = moles x molar mass

from periodic table   the molar mass of ag =107.87 g/mol

mass   = 0.472   moles x 107.87 g/mol = 50.9 g

3.   the   much   silver   collected worth is   1.797 oz

  convert   50.9 g   to oz

that is   1 gram = 0.0353 oz

          50.9 grams =?   oz

by cross multiplication

={(50.9 grams x 0.0353 oz) / 1   gram}   =1.797 oz

a

explanation:

no diagram was provided, but i'm guessing it's the one i've attached to my answer.

here, a mechanical force turns the rod.   this generates an electric current in the coil, which powers the bulb.