"The audience  is my batch in the faculty (Education) and the professor told us to find  any 2 topics to talk about in the course of CONVERSATION  And we need something interesting and simple just for 5 minutes."

There's a kind of self-help fraternal organization called Toastmasters that helps people improve presentation skills. One of the standard exercises in a Toastmaster's session is called "Table Topics," and it is a challenge to speak extemporaneously for about five minutes on a topic--one that you don't know in advance. If you Google on toastmasters table topics you will get dozens of hits on lists of ideas for table topics.

Here are a few I got from the first hit:

1 - Holiday themes: begin by looking at these holidays as sources for theme-based questions

7 – Flicks That Flunk: The speaker picks a really bad movie they have seen. They then must persuade the audience to see it.

8 – Words of Wisdom: ... I keep handy a book of sayings/proverbs in case I have to serve as last-minute Table Topics Master. I ask Table Topics respondents to randomly pick a page number and I read one of the sayings and ask them to speak on that saying.

9 – This Day In History: This Table Topics theme requires a bit of research on the part of the Table Topics Master, who creates questions based on historical events that occurred on the day of the Toastmasters meeting. Each event in history can serve as a basis for a question. Table Topics Masters can go on the internet and use any number of popular search engines to get information on past events that occurred on “This Day in History.”

And from the second: If you could fly in a hot-air balloon over any city in the world, what city would you choose?

If you could go back in time and talk to yourself at the age of ten, what advice would you give yourself?

It would help if you told us about your audience, and how long the essay should be. Here are a few random ideas. Maybe one of them will help.

a) How deep is the ocean?

b) What is the best way to make coffee?

c) Why don't children like food that tastes sour or bitter?

d) Should languages be logical? Should we get rid of irregular verbs?

e) Was the world better a century ago?