The diagram shows refraction of a ray of light as it passes through three transparent substances, L, M and N. The speeds of light in the three substances are vL, vM and vN, respectively.
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Which of the following shows the relationship between vL, vM and vN?
vL > vM > vN
vL > vN > vM
vN > vM > vL
vM > vN > vL
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