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Electric Charges and Fields — Physics STD 12 Science — Question

Rajasthan BoardEnglish MediumSTD 12 SciencePhysicsElectric Charges and Fields4 Marks
Question
Two large, thin metal plates are parallel and close to each other. On their inner faces, the plates have surface charge densities of opposite signs and of magnitude $17.0 \times 10^{-22} C / m ^2$. What is E: (a) in the outer region of the first plate, (b) in the outer re-gion of the second plate, and (c) between the plates?
✓

Answer

Given :
$\sigma=17 \cdot 0 \times 10^{-22} C / m ^2$
Electric field produced due to layer of charge
$E =\frac{\sigma}{2 \in_0}$
Image

If the electric field due to the positive charge layer is E1 end ,the electric field due to the negative charge layer is E2 then (a) and (b) Electric field at the outer points of the plates
$E=E_1-E_2$
or$E=\frac{\sigma}{2 \in_0}-\frac{\sigma}{2 \in_0}=0$
(c)$E=\frac{\sigma}{2 \in_0}+\frac{\sigma}{2 \in_0}=\frac{\sigma}{\in_0}$
[From positive to negative plate]
On putting values $E =\frac{17 \times 10^{-}}{8.85 \times 10^{-12}}$
$=1.92 \times 10^{-10} N / C$

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