A. periscope
B. telescope
C. kaleidoscope
D. spectroscope
✅ The correct answer is option A.
For seeing objects at the surface of water from a submarine under water, the instrument used is periscope. It can be through or around the object that made it visible. In addition to this, it avoids any sort of direct sight line from the point of observation to the object being observed.
For seeing objects at the surface of water from a submarine under water, the instrument used is periscope. It can be through or around the object that made it visible. In addition to this, it avoids any sort of direct sight line from the point of observation to the object being observed.