Light will change its path if the refractive indexes of the 2 mediums are different. if the refractive indexes of two mediums are same, it will not change its path as its speed wont change.
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Yes , The formula for angle of refraction is n1 (sinx)= n2 (siny) , where x and y being angle of incidence and refraction respectively. So here angle of incidence is zero . Sin0=0, hence angle of refraction is also zero.And hence the light travels without any change of path.