3. Which of the following relations is correct for dispersive power?
Answers
Answer:
The refractive index (μ) for glass prism is given by μ=sin(2A)2sin(A+δ) , where A is the central angle of prism, δ is the angle of deviation .
For small angle of A and δ , 2sin(A+δ)≈2A+δ,2sin(A)≈2A
Then δ=(μ−1)A,
If δv andδr are the deviations produced for the violet and red rays and μv and μr are the corresponding refractive indices of the material of the small angled prism then angular dispersion (difference in deviation between the extreme colors) is given by δv−δr=(μv−μr)A.
Similarly deviation for yellow light is given by δy=(μy−1)A.
Now dispersive power (ω) of the material is defined as (ω)=δyδv−δr .
Thus ω=(μy−1)A(μv−μr)A=(μy
Answer:
The refractive index (μ) for glass prism is given by μ=sin(2A)2sin(A+δ) , where A is the central angle of prism, δ is the angle of deviation .
For small angle of A and δ , 2sin(A+δ)≈2A+δ,2sin(A)≈2A
Then δ=(μ−1)A,
If δv andδr are the deviations produced for the violet and red rays and μv and μr are the corresponding refractive indices of the material of the small angled prism then angular dispersion (difference in deviation between the extreme colors) is given by δv−δr=(μv−μr)A.
Similarly deviation for yellow light is given by δy=(μy−1)A.
Now dispersive power (ω) of the material is defined as (ω)=δyδv−δr .
Thus ω=(μy−1)A(μv−μr)A=(μy
Explanation: