state gov APPSC Forest/Assistant Beat Officer (ఫారెస్ట్/అసిస్టెంట్ బీట్ ఆఫీసర్) (Pre + Mains) Mock Test 2025 General Knowledge Science Technology and Inventions
The optical instrument that is used by Army personnel to see their enemies while hiding themselves is :
1
Stethoscope
2
Simple Microscope
3
Compound Microscope
4
Periscope