why architecture showing UNKNOWN! for cross compiled executable file

hellow_world_arm is a finaly binary or exectuable program which is cross compiled in linux for arm board.

why objdump showing architecture as UNKNOWN, is it expected behaviour.

(base) prashad@ubuntu:~/Downloads$ objdump -a -x hello_world_arm 
hello_world_arm:     file format elf32-little
hello_world_arm
architecture: UNKNOWN!, flags 0x00000112:
EXEC_P, HAS_SYMS, D_PAGED
start address 0x00008894

(base) prashad@ubuntu:~/Downloads$ file hello_world_arm 
hello_world_arm: ELF 32-bit LSB executable, ARM, version 1 (ARM), dynamically linked, interpreter /lib/ld-, for GNU/Linux 2.4.3, with debug_info, not stripped