A very long, 1.0-mm-diameter wire carries a 1.8 A current from left to right. Thin plastic insulation on the wire is positively charged with linear charge density 2.8 nC/cm. A mosquito 1.0 cm from the center of the wire would like to move in such a way as to experience an electric field but no magnetic field. How fast should she fly in m/s and in which direction?
-
If she flies to the right, there is charge is moving past her to the left, which looks like a current to the left. She must fly fast enough for it to look like there is 1.8 A of current to the left, balancing the current to the right. So she must pass 1.8 coulombs/sec. The linear charge density is:
λ = 2.80*10^-9 C/cm * 100 cm/m = 280*10^-9 C/m
I = λ*v
v = I / λ = 1.8 / 280*10^-9 = 6.4*10^6 m/s, to the right
That's one fast bug!!
λ = 2.80*10^-9 C/cm * 100 cm/m = 280*10^-9 C/m
I = λ*v
v = I / λ = 1.8 / 280*10^-9 = 6.4*10^6 m/s, to the right
That's one fast bug!!