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Two transparent media A and B are separated by a plane boundary. The speed of light in medium A is 2.0 x 108 ms-1 and in medium, B is 2.5 x 108 ms-1. The critical angle for which ray of light going from A to B suffers total internal reflection is?
By BYJU'S Exam Prep
Updated on: September 25th, 2023
(a) sin-1 (½)
(b) sin-1 (⅖)
(c) sin-1 (⅘)
(d) sin-1 (⅗)
The critical angle for which the ray of light going from A to B suffers total internal reflection is sin-1 (⅘). Steps to The critical angle for which the ray of light going from A to B suffers total internal reflection:
Step 1: The necessary inclination for complete internal reflection
- The incidence angle above which 100% internal reflection takes place is known as the critical angle.
- Different forms of waves, including light waves, electromagnetic waves, sound waves, etc., exhibit total internal reflection.
Step 2: Now we have to calculate the light’s velocity ratio in medium A.
nA = c/vA
Here, c denotes the speed of light in air, vA denotes the velocity of light in medium A, and nA denotes the ratio of the velocities of light in medium A.
nA = 3 x 108 ms-1/ 2.0 x 108 ms-1
On simplifying we get
nA = 1.5
Step 3: Now we have to calculate the ratio of the velocities of light in media B.
nB = c/vB
Here, nB is the ratio of the velocities of light in media B, and vB is the velocity of light in media B.
nB = 3 x 108 ms-1/ 2.5 x 108 ms-1
On simplifying we get
nB = 1.2
Step 4: Now we have to calculate the critical angle
The critical angle can be calculated using the formula: sin (ic) = nB/nA
Here, ic is the critical angle
Substituting the values in the formula we get:
sin (ic) = 1.2/1.5
ic = sin-1 (⅘)
The critical angle for 100% internal reflection of the beam is sin-1 (⅘)
Summary:
Two transparent media A and B are separated by a plane boundary. The speed of light in medium A is 2.0 x 108 ms-1 and in medium, B is 2.5 x 108 ms-1. The critical angle for which the ray of light going from A to B suffers total internal reflection is?
Two transparent media A and B are separated by a plane boundary. The speed of light in medium A is 2.0 x 108 ms-1 and in medium, B is 2.5 x 108 ms-1. The critical angle for which ray of light going from A to B suffers total internal reflection is sin-1 (⅘).