Please give me the reasons for answer of these two questions in the image .

Dear Preeti
Please ask one question in one thread.
Answer of question 1-
In case of reflection and refraction, angle is always measured from the normal to the incident point.
So, when ray incidents normally, that means angle is 0° . And according to the law of reflection,
∠i = ∠r
so, angle of reflection will be 0° that means it is reflected back on the same path.
Regards
Arun (askIITians forum expert)