Two students are situated in a room 10 m high, they are separated by 7 m high partition wall. The students are unable to see each other even though they can converse easily. But they know that both light and sound waves can bend around the obstacles. So they were interested to know scientific cause of such phenomena. Then they went to their friend Neelam who convinced them with basic facts. 

(a) What are the values shown by Neelam ? 

(b) How did Neelam convince them such basic facts ?