Answer:
No Refraction takes places
Explanation:
When light travels from one medium to another at an angle of incidence 0 degree then no refraction takes place .
It is because according to Refraction law
sini =
sinr
where are the refractive index of medium of incidence and medium of refraction .
When i = 0 , left side of the equation becomes 0 and thus r (angle of refraction) must be zero. So No refraction takes place
Substract two consecutive terms of the sequence to see if there is a common difference:
As we can see, there is a common difference of -6.
Then, if a number of the sequence is given, the next one can be found by adding -6 (which is the same as subtracting 6).
Notice that the first term of the sequence is 3.
Then, the rule for the sequence is to start with 3 and add -6 repeatedly.
Therefore, the correct choice is option A) Start with 3 and add -6 repeatedly.