Question

i want 4 th one pls send fast pls with explanation steps

Answer 1

Answer:

.s..........1...

Explanation:

.....thanks

mark as brainiest

Answer 2

Answer:

Explanation:

refractive index to A with respect to B;

$n_{AB} = \frac{velocity of A}{velocity of B}$

        = $\frac{1.6}{2.8} = \frac{4}{7}$