what is the units of the value of lm35 ,does lm35 gives negative value , if it doesn’t give negative values how can we calculate temperature in case of negative degree celsius

It is possible that may be you have connected lm35 wrongly kindly double check your circuit connection.

LM 35 output is in voltage proportional to temperature to convert it to celsius divide lm 35 outuput by 10.24

every thing is good dude but the problem is lm35/10.24 is wrong formula because the reading is between 0 to 1024 in this case if the external temperature in -5 celsius you can’t get by this formula