Could someone pls help me out?
In this mcq could someone explain to me how we got the ratio of the drift speeds? I know it's from the I = navq formula but how? TT
The answer is A
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Unit 2 electricity q watch
- 14-02-2018 12:29
- 14-02-2018 13:36
I would rearrange so I can see more clearly what the drift speed depends on
v = I/naq
The n and q don't change so essentially we have v α I/a. The thing to watch is that if A has twice the diameter of B, then it has area a 4x as big.
Does that help? Look for a row in the table which would fit the v α I/a relationship.
- 14-02-2018 13:48
That clears things up a bit. Thank you =D I just don't understand one thing though. How would the area of A be 4 times as big as area of B? Why not twice?
- 14-02-2018 13:51
Yikes, and having read it properly this time, if they're in series, the current must be the same in both, so that knocks out C and D and gives you a 50/50 chance of guessing