Sorry its my mistake and i used set_time resolution at the time of elaboration, but didn't notice my sc_clock declaration.
Before (error)
sc_clock clk("clk",20, SC_FS);
sc_set_time_resolution(1,SC_FS);
After (start working)
sc_set_time_resolution(1,SC_FS);
sc_clock clk("clk",20, SC_FS);
Thanks and closing the topic.
Regards, Prasanna