padna = the action describing the act of farting (passing of copious amounts of vicious human gas).
*EXAMPLE: *us nay haleem khay kay woh padna shuroo kiya keh koi haad hi nahi
Parhna = the action describing the act of studying
*EXAMPLE: *us nay abhi tak finals kay liyay parhna nahi shuroo kya, bara nalaiq hai
thanks for clarification, i blame english alphabets for this