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Zorluk: OrtaRefraction of Light, Total Internal Reflection, and Prisms

A glass prism with a refracting angle of 6060^\circ has a refractive index of 2\sqrt{2}. What is the angle of minimum deviation, in degrees, experienced by a light ray passing through this prism?

Cevap: 30 degrees

Cevap

The angle of minimum deviation is 3030^\circ.
Using the prism minimum deviation relation n=sin((A+Dm)/2)sin(A/2)n = \frac{\sin\left((A + D_m)/2\right)}{\sin(A/2)}, substituting n=2n = \sqrt{2} and A=60A = 60^\circ yields sin((60+Dm)/2)=12\sin\left((60^\circ + D_m)/2\right) = \frac{1}{\sqrt{2}}. This gives (60+Dm)/2=45(60^\circ + D_m)/2 = 45^\circ, so Dm=30D_m = 30^\circ.

Adım Adım Çözüm

1
Apply the prism minimum deviation equation.
n=sin(A+Dm2)sin(A2)n = \frac{\sin\left(\frac{A + D_m}{2}\right)}{\sin\left(\frac{A}{2}\right)}
This relates refractive index, prism refracting angle, and minimum deviation angle.
2
Substitute the given values A=60A = 60^\circ and n=2n = \sqrt{2}.
2=sin(60+Dm2)sin(30)\sqrt{2} = \frac{\sin\left(\frac{60^\circ + D_m}{2}\right)}{\sin(30^\circ)}
Dividing the refracting angle 6060^\circ by 2 gives 3030^\circ for the denominator angle.
3
Calculate the numerator sine term.
sin(60+Dm2)=12\sin\left(\frac{60^\circ + D_m}{2}\right) = \frac{1}{\sqrt{2}}
Multiplying 2\sqrt{2} by sin(30)=0.5\sin(30^\circ) = 0.5 gives 22=12\frac{\sqrt{2}}{2} = \frac{1}{\sqrt{2}}.
4
Solve for the angle DmD_m.
Dm=30D_m = 30^\circ
Since arcsin(12)=45\arcsin\left(\frac{1}{\sqrt{2}}\right) = 45^\circ, we have 60+Dm2=45\frac{60^\circ + D_m}{2} = 45^\circ, leading to 60+Dm=9060^\circ + D_m = 90^\circ.

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