Question

A copper wire has diameter 0.5 mm and resistivity of 1.6 × 10–8 Ω m. What will be
the length of this wire to make its resistance 10 Ω? How much does the resistance
change if the diameter is doubled?

Answer 1

Answer:

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Explanation:

∆R=7.5 ohms

Answer 2

ʜᴇʏᴀ ᴍᴀᴛᴇ!!

ʜᴇʀᴇ ɪs ᴜʀ ᴀɴsᴡᴇʀ ⏬ ⏬

ɢɪᴠᴇɴ,

ᴅɪᴀᴍᴇᴛᴇʀ ᴏғ ᴄᴏᴘᴘᴇʀ ᴡɪʀᴇ = 0.5ᴍᴍ = 5 × 10-⁴ ᴍ

ʀᴇsɪsᴛɪᴠɪᴛʏ = 1.6 × 10^-8 ᴏʜᴍ.ᴍ

ʀᴇsɪsᴛᴀɴᴄᴇ = 10 ᴏʜᴍ

ʟᴇɴɢᴛʜ = ?

ᴡᴇ ᴋɴᴏᴡ,

ʀ = ᴅʟ/ᴀ

ᴡʜᴇʀᴇ ʀ , ᴅ , ʟ ᴀɴᴅ ᴀ ᴀʀᴇ ʀᴇsɪsᴛᴀɴᴄᴇ , ʀᴇsɪsᴛɪᴠɪᴛʏ , ʟᴇɴɢᴛʜ ᴀɴᴅ ᴄʀᴏss sᴇᴄᴛɪᴏɴ ᴀʀᴇᴀ.

10 = 1.6 × 10^-8 × ʟ/(πʀ²)

ʟ = 10 × 3.14 × (2.5 × 10^-4)² × 10^8/1.6

ʟ = 10× 3.14 × 6.25/1.6

ʟ = 122.656 ᴍ