Question

Derive potential energy per unit volume that is energy density
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Answer 1

Energy density is the amount of energy stored in a given system or region of space per unit volume. Colloquially it may also be used for energy per unit mass, though the accurate term for this is specific energy.

Answer 2

Eɴᴇʀɢʏ ᴅᴇɴsɪᴛʏ ɪs ᴛʜᴇ ᴀᴍᴏᴜɴᴛ ᴏғ ᴇɴᴇʀɢʏ sᴛᴏʀᴇᴅ ɪɴ ᴀ ɢɪᴠᴇɴ sʏsᴛᴇᴍ ᴏʀ ʀᴇɢɪᴏɴ ᴏғ sᴘᴀᴄᴇ ᴘᴇʀ ᴜɴɪᴛ ᴠᴏʟᴜᴍᴇ. Cᴏʟʟᴏϙᴜɪᴀʟʟʏ ɪᴛ ᴍᴀʏ ᴀʟsᴏ ʙᴇ ᴜsᴇᴅ ғᴏʀ ᴇɴᴇʀɢʏ ᴘᴇʀ ᴜɴɪᴛ ᴍᴀss, ᴛʜᴏᴜɢʜ ᴛʜᴇ ᴀᴄᴄᴜʀᴀᴛᴇ ᴛᴇʀᴍ ғᴏʀ ᴛʜɪs ɪs sᴘᴇᴄɪғɪᴄ ᴇɴᴇʀɢʏ.