The light incident on a smooth reflecting surface undergoes specular reflection. the angle of reflection is 55°. what can you say about the angle of incidence?
a) it's greater than 55°.
b) it's less than 55°.
c) it's equal to 55°.
d) it could be any angle between 0° to 90°.

The correct answer is option (c).

Explanation:

According Laws of reflection:

1) The angle of incidence is equal to the angle of reflection, ∠i=∠r.

2)The incident ray , reflected ray and the normal drawn to the surface of the mirror (here smooth reflecting surface) all lies in the sample plane.

So, according to the question a light is reflected back at the angle of 55° which means that angle of the incident ray with the reflection surface is 55° .

Hence the correct answer is option(c).

  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

scientific laws are the result of testing theories and proving them to be facts.