Pada segitiga abc terdapat muatan pada sisi B dan C berturut-turut 9 mikro coulomb dan 3 mikro coulomb. Hitung kuat medan di A jika panjang sisinya 3cm

Listrik Statis
- Medan Listrik

[tex] Q_A [/tex] = + 9 μC = + 9 × 10⁻⁶ C
[tex] Q_B [/tex] = + 3 μC = + 3 × 10⁻⁶ C

[tex] E_A = \frac{k \cdot Q_A}{r^2} \\
E_A = \frac{9 \times 10^9 \cdot 9 \times 10^{-6}}{(3 \times 10^{-2})^2} \\
E_A = \frac{9 \times 9 \times 10^3}{9 \times 10^{-4}} \\
E_A = 9 \times 10^7 \ N/C [/tex]

[tex] E_B = \frac{k \cdot Q_B}{r^2} \\
E_B = \frac{9 \times 10^9 \cdot 3 \times 10^{-6}}{(3 \times 10^{-2})^2} \\
E_B = \frac{9 \times 3 \times 10^3}{9 \times 10^{-4}} \\
E_B = 3 \times 10^7 \ N/C [/tex]

Maka ,

[tex] E_A = \sqrt{E_B^2 + E_C^2 + 2 E_B E_C \cos \alpha} \\
E_A = \sqrt{(9 \times 10^7)^2 + (3 \times 10^7)^2 + 2(9 \times 10^7)(3 \times 10^7) \cos 60} \\
E_A = \sqrt{(81 + 9 + 27) \times 10^{14}} \\
E_A = 3 \times 10^7 \sqrt{13} \ N/C [/tex]

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