Question

1. Define the term principal axis of a spherical mirror
OR​

Answer 1

Answer:

a line passing through the center of the surface of a lens or spherical mirror and through the centers of curvature of all segments of the lens or mirror.

Answer 2

Answer:

ᴀ ʟɪɴᴇ ᴘᴀssɪɴɢ ᴛʜʀᴏᴜɢʜ ᴛʜᴇ ᴄᴇɴᴛᴇʀ ᴏғ ᴛʜᴇ sᴜʀғᴀᴄᴇ ᴏғ ᴀ ʟᴇɴs ᴏʀ sᴘʜᴇʀɪᴄᴀʟ ᴍɪʀʀᴏʀ ᴀɴᴅ ᴛʜʀᴏᴜɢʜ ᴛʜᴇ ᴄᴇɴᴛᴇʀs ᴏғ ᴄᴜʀᴠᴀᴛᴜʀᴇ ᴏғ ᴀʟʟ sᴇɢᴍᴇɴᴛs ᴏғ ᴛʜᴇ ʟᴇɴs ᴏʀ ᴍɪʀʀᴏʀ.