Question

The magnifying power of a converging lens used as a simple microscope is 1+D/f. A compound microscope is a combination of two such converging lenses. Why don’t we have magnifying power( 1+D/ fo) (1+D/fe)?In other words, why can the objective not be treated as a simple microscope but the eyepiece can?

Answer 1

• Converging lens is used in a simple microscope to magnify the object.

• To serve this purpose we use  eyepiece in a compound microscope.

• But  objective lens is used  to form an enlarged, real and inverted image of the object at a distance less than the focal length of the eyepiece.

• So, its magnification power cannot be expressed in a way it is expressed for a simple microscope.

Answer 2

I have explained the answer below---------

ᴄᴏɴᴠᴇʀɢɪɴɢ ʟᴇɴs ɪs ᴜsᴇᴅ ɪɴ ᴀ sɪᴍᴘʟᴇ ᴍɪᴄʀᴏsᴄᴏᴘᴇ ᴛᴏ ᴍᴀɢɴɪғʏ ᴛʜᴇ ᴏʙᴊᴇᴄᴛ.

ᴛᴏ sᴇʀᴠᴇ ᴛʜɪs ᴘᴜʀᴘᴏsᴇ ᴡᴇ ᴜsᴇ  ᴇʏᴇᴘɪᴇᴄᴇ ɪɴ ᴀ ᴄᴏᴍᴘᴏᴜɴᴅ ᴍɪᴄʀᴏsᴄᴏᴘᴇ.

ʙᴜᴛ  ᴏʙᴊᴇᴄᴛɪᴠᴇ ʟᴇɴs ɪs ᴜsᴇᴅ  ᴛᴏ ғᴏʀᴍ ᴀɴ ᴇɴʟᴀʀɢᴇᴅ, ʀᴇᴀʟ ᴀɴᴅ ɪɴᴠᴇʀᴛᴇᴅ ɪᴍᴀɢᴇ ᴏғ ᴛʜᴇ ᴏʙᴊᴇᴄᴛ ᴀᴛ ᴀ ᴅɪsᴛᴀɴᴄᴇ ʟᴇss ᴛʜᴀɴ ᴛʜᴇ ғᴏᴄᴀʟ ʟᴇɴɢᴛʜ ᴏғ ᴛʜᴇ ᴇʏᴇᴘɪᴇᴄᴇ.
sᴏ, ɪᴛs ᴍᴀɢɴɪғɪᴄᴀᴛɪᴏɴ ᴘᴏᴡᴇʀ ᴄᴀɴɴᴏᴛ ʙᴇ ᴇxᴘʀᴇssᴇᴅ ɪɴ ᴀ ᴡᴀʏ ɪᴛ ɪs ᴇxᴘʀᴇssᴇᴅ ғᴏʀ ᴀ sɪᴍᴘʟᴇ ᴍɪᴄʀᴏsᴄᴏᴘᴇ.