john25:
We all know that op amps means operational amplifier. But how much amplification can a uA741 can do? Can this op amp amplify upto 1000 times?
Yes, most any opamp can. Open circuit gain (when there is no negative feedback being applies) on most opamps is over 100db (at DC, AC gain is a little more complex to express), that's a gain of 10,000,000,000 if I recall by db conversions correctly. Practical circuit gain using opamps is determined by the ratio of external resistors wired to the opamp to form a classic negative feedback DC amplifier, not by any limitation of the opamp.
More important is that you really shouldn't be using 741 type opamps as it's a second generation opamp dating back forty plus years or so. It has many practical circuit limitiations and very poor specifications for this day and age. Their only remaining purpose in life should be as replacement parts for old existing equipment that used them and are now in need of repair. Much newer opamps with much better specs and as cheap or cheaper then a 741 are easily avalible. Bottom line, ditch the 741s and use real opamps.