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1. In your recent Refraction Lab, you observed an unusual observation - a discrepant event - depicted in the below diagram.

a) A ray of light was sent from air through a glass block in the shape of an isosceles triangle. This ray of light passed across the first boundary without (1 word) since it was incident (3 words).

b) The ray of light then traveled  in a straight line through glass until it reached the second boundary. Despite our expectations, instead of transmitting across this boundary, the entirety of the light seemed to  (2 words) the boundary and transmit out the (2 words) of the isosceles triangle.

2. Total Internal Reflection (TIR) involves the  (6 words) off the boundary.

TIR only takes place when both of the following conditions are met:

a) the light comes from the (2 words) medium and approaching the (2 words) medium.

b) the angle of   (1 word) is greater than the so-called (2 words).

3. Check out the diagram below to completely understand the TIR.

a) At angle of incidence close to 0 degrees, most of the light energy is   (1 word) across the boundary and very little of it is (1 word).

b)  That is, as the angle of incidence is increased, the brightness of the refracted ray (1 word) and the brightness of the reflected ray (1 word).

c) Since the light waves would refract (2 words) the normal - a case of the (3 letters, abbreviation) principle of refraction-, the angle of refraction would be (1 word) than the angle of incidence. And if this is the case, the angle of refraction would also be (1 word) than the angle of reflection (since the angles of reflection and incidence are (2 words)).

d) As the angle of incidence is increased, the angle of refraction would eventually reach a (2 words) angle.

4. a) The critical angle is defined as the angle of (1 word) which provides an angle of (1 word) of (number) degrees.

b) The actual value of the critical angle is dependent upon the (3 words) present on each side of the boundary. For the (2 words) boundary, the critical angle is 48.6-degrees. For the crown glass-water boundary, the critical angle is (number) degrees.

c) Total internal reflection only occurs with (1 word) angles of incidence, that are larger than the (2 words).

5. a) Total Internal Reflection is the fundamental principle which explains how (2 words) work; they are used in communication systems and micro-surgeries. TIR takes places within it, so no incident energy is lost due to the transmission of light across the boundary.

b) Some optical instruments, such as (1 word) and (1 word) use trigonal  prisms instead of mirrors to reflect light around corners. Light typically enters perpendicular to the face of the prism, undergoes TIR off the opposite face and then exits out the third face.