• Livestream AMA: Join SDN as we welcome Dr. John Ligon, a Pediatric Oncologist with the National Cancer Institute on May 11th at 8:00 PM Eastern. Register now!

ssiding

10+ Year Member
Aug 20, 2008
41
0
Status (Visible)
  1. Pre-Medical
You have two adajacent transparent media. The speed of ligght through medium 1 is v1, and the speed of light through medium 2 is v2. If v1 < v2, then total internal reflection will occur at the interface between these media if a beam of light is

A. incident in medium 1 and strikes the interface at an angle of incidence greater than arcsin (v1/v2)

B. incident in medium 1 and strikes the interface at an angle of incidence greater than arcsin (v2/v1)

C. incident in medium 2 and strikes the interface at an angle of incidence greater than arcsin (v1/v2)

D. incident in medium 2 and strikes the interface at an angle of incidence greater than arcsin (v2/v1)
 

soby10

10+ Year Member
5+ Year Member
Apr 27, 2008
56
0
Status (Visible)
  1. Pre-Medical
Since n=c/v and v2>v1 so n1>n2. Total internal reflection occurs when light passes through medium of larger refractive index to a smaller refractive index and the refractive ray bends away from the normal, angle of refraction increases and so does angle of incidence. When angle of incidence is at a critical angle the angle of refraction is 90. So when angle of incidence is larger than critical angle total internal reflection occurs so there is no refracted light, all light is in medium. The def. of critical angle is sin crit. angle= n2/n1 (n1>n2). Therefore, light is travelling from bigger index n1 to n2 the smaller index. Since v2 is inversely related to n2 and v1 is inversely related to n1 ,(c/ v2)/(c/v1) ---> (c/v2) *(v1/c) = v1/v2 so angle is at arcsin v1/v2 answer is A.
 

isaacmn

10+ Year Member
May 5, 2007
29
0
International programs
Status (Visible)
  1. Medical Student
total internal reflection occurs when you have a light incident on a medium of high refractive index to low. The light will be trapped and internal reflection. Also when theta incidence is greater than theta critical.

agree with the last post. if v1<v2 n1>n2 ..which elimiated C and D
 
About the Ads
This thread is more than 12 years old.

Your message may be considered spam for the following reasons:

  1. Your new thread title is very short, and likely is unhelpful.
  2. Your reply is very short and likely does not add anything to the thread.
  3. Your reply is very long and likely does not add anything to the thread.
  4. It is very likely that it does not need any further discussion and thus bumping it serves no purpose.
  5. Your message is mostly quotes or spoilers.
  6. Your reply has occurred very quickly after a previous reply and likely does not add anything to the thread.
  7. This thread is locked.