Question

Question no 12
Question is attached in picture

Answer 1

As in the attached image, we get that the angle of incident is 10°.

Similarly, the angle of reflection from the mirror M2 will be 10°.

HOPE THIS COULD HELP!!!

Answer 2

Explanation:

Given: d=3

We know:

an=a+(n−1)d

∴a20−a15=[a+19d]−[a+14d]

                     =5d

                     =5×3

                     =15

Hence, the answer is 15.

Given: d=3

We know:

an=a+(n−1)d

∴a20−a15=[a+19d]−[a+14d]

                     =5d

                     =5×3

                     =15

Hence, the answer is 15.