Chapter 18. Current and drift speed (18-3)

Question

rJOPXETnLcDo2xVUF4O+DyQMJUkAVXDh
{"title":"Current in a wire","description":"Correct!","type":"correct","color":"#99CCFF","code":"[{\"shape\":\"poly\",\"coords\":\"82,133\"},{\"shape\":\"rect\",\"coords\":\"10,16,12,16\"},{\"shape\":\"poly\",\"coords\":\"144,22\"},{\"shape\":\"rect\",\"coords\":\"2,9,22,53\"}]"} {"title":"Number of moving charges per unit volume","description":"Wrong","type":"incorrect","color":"#ffcc00","code":"[{\"shape\":\"rect\",\"coords\":\"77,17,113,55\"}]"} {"title":"Speed at which charges drift through the wire","description":"Incorrect","type":"incorrect","color":"#00ff00","code":"[{\"shape\":\"rect\",\"coords\":\"183,24,206,54\"}]"} {"title":"Magnitude of the charge on each moving charge","description":"Incorrect","type":"incorrect","color":"#000080","code":"[{\"shape\":\"rect\",\"coords\":\"154,24,182,54\"}]"} {"title":"Cross-sectional area of the wire","description":"Incorrect","type":"incorrect","color":"#333333","code":"[{\"shape\":\"rect\",\"coords\":\"115,9,149,53\"}]"}

Question

Jcs4BAIm0s4M168AH2k9qHB3qY5weDiDPRpvbBesqZpZxHInHk/VQHAWE7k=
{"title":"Current in a wire","description":"Incorrect","type":"incorrect","color":"#99CCFF","code":"[{\"shape\":\"poly\",\"coords\":\"82,133\"},{\"shape\":\"rect\",\"coords\":\"10,16,12,16\"},{\"shape\":\"poly\",\"coords\":\"144,22\"},{\"shape\":\"rect\",\"coords\":\"2,9,22,53\"}]"} {"title":"Number of moving charges per unit volume","description":"Correct!","type":"correct","color":"#ffcc00","code":"[{\"shape\":\"rect\",\"coords\":\"77,17,113,55\"}]"} {"title":"Speed at which charges drift through the wire","description":"Incorrect","type":"incorrect","color":"#00ff00","code":"[{\"shape\":\"rect\",\"coords\":\"183,24,206,54\"}]"} {"title":"Magnitude of the charge on each moving charge","description":"Incorrect","type":"incorrect","color":"#000080","code":"[{\"shape\":\"rect\",\"coords\":\"154,24,182,54\"}]"} {"title":"Cross-sectional area of the wire","description":"Incorrect","type":"incorrect","color":"#333333","code":"[{\"shape\":\"rect\",\"coords\":\"115,9,149,53\"}]"}

Question

84I/HplHg68BVuraU17MYohL3G0tGi2xx8869mz/GYLe2x/1MBXLpQq+0n1kVTdJa2HBpw==
{"title":"Current in a wire","description":"Incorrect","type":"incorrect","color":"#99CCFF","code":"[{\"shape\":\"poly\",\"coords\":\"82,133\"},{\"shape\":\"rect\",\"coords\":\"10,16,12,16\"},{\"shape\":\"poly\",\"coords\":\"144,22\"},{\"shape\":\"rect\",\"coords\":\"2,9,22,53\"}]"} {"title":"Number of moving charges per unit volume","description":"Wrong","type":"incorrect","color":"#ffcc00","code":"[{\"shape\":\"rect\",\"coords\":\"77,17,113,55\"}]"} {"title":"Speed at which charges drift through the wire","description":"Correct!","type":"correct","color":"#00ff00","code":"[{\"shape\":\"rect\",\"coords\":\"183,24,206,54\"}]"} {"title":"Magnitude of the charge on each moving charge","description":"Incorrect","type":"incorrect","color":"#000080","code":"[{\"shape\":\"rect\",\"coords\":\"154,24,182,54\"}]"} {"title":"Cross-sectional area of the wire","description":"Incorrect","type":"incorrect","color":"#333333","code":"[{\"shape\":\"rect\",\"coords\":\"115,9,149,53\"}]"}

Question

l9Wz+MzFtikBgde8+/8GuN1s96xk8YQnBMIVtRvMMA5VFfdw8VJPz499OXmhLS+4IZpplw==
{"title":"Current in a wire","description":"Incorrect","type":"incorrect","color":"#99CCFF","code":"[{\"shape\":\"poly\",\"coords\":\"82,133\"},{\"shape\":\"rect\",\"coords\":\"10,16,12,16\"},{\"shape\":\"poly\",\"coords\":\"144,22\"},{\"shape\":\"rect\",\"coords\":\"2,9,22,53\"}]"} {"title":"Number of moving charges per unit volume","description":"Wrong","type":"incorrect","color":"#ffcc00","code":"[{\"shape\":\"rect\",\"coords\":\"77,17,113,55\"}]"} {"title":"Speed at which charges drift through the wire","description":"Incorrect","type":"incorrect","color":"#00ff00","code":"[{\"shape\":\"rect\",\"coords\":\"183,24,206,54\"}]"} {"title":"Magnitude of the charge on each moving charge","description":"Correct!","type":"correct","color":"#000080","code":"[{\"shape\":\"rect\",\"coords\":\"154,24,182,54\"}]"} {"title":"Cross-sectional area of the wire","description":"Incorrect","type":"incorrect","color":"#333333","code":"[{\"shape\":\"rect\",\"coords\":\"115,9,149,53\"}]"}

Question

rMGPa3H70BqBaMgdoA3GHV5ibGhB5huzvlEEnAPt+IUIrTYm
{"title":"Current in a wire","description":"Incorrect","type":"incorrect","color":"#99CCFF","code":"[{\"shape\":\"poly\",\"coords\":\"82,133\"},{\"shape\":\"rect\",\"coords\":\"10,16,12,16\"},{\"shape\":\"poly\",\"coords\":\"144,22\"},{\"shape\":\"rect\",\"coords\":\"2,9,22,53\"}]"} {"title":"Number of moving charges per unit volume","description":"Wrong","type":"incorrect","color":"#ffcc00","code":"[{\"shape\":\"rect\",\"coords\":\"77,17,113,55\"}]"} {"title":"Speed at which charges drift through the wire","description":"Incorrect","type":"incorrect","color":"#00ff00","code":"[{\"shape\":\"rect\",\"coords\":\"183,24,206,54\"}]"} {"title":"Magnitude of the charge on each moving charge","description":"Wrong","type":"incorrect","color":"#000080","code":"[{\"shape\":\"rect\",\"coords\":\"154,24,182,54\"}]"} {"title":"Cross-sectional area of the wire","description":"Correct!","type":"correct","color":"#333333","code":"[{\"shape\":\"rect\",\"coords\":\"115,9,149,53\"}]"}

Review

The number of moving charges per volume (\(n\)) is different for different materials. Equation 18­-3 tells us that for a wire made of a given material and with a given cross-sectional area \(A\), the current \(i\) is directly proportional to the drift speed.