Formula Sheet
9 2 2
𝑘 is Coulombs Constant(8. 99 · 10 𝑁𝑚 /𝐶 )
1. Electrostatics
1. Coulomb’s Law
𝑞1𝑞2
𝐹𝑒 = 𝑘 2
𝑟
● 𝐹𝑒 is the electric force
Q
● are the charges on the two objects
● r is the distance between the two objects
2. E
lectric Field (point charge)
𝐹 𝑄
𝐸 = 𝑞 = 𝑘 2
𝑟
● E = electric field (N/C)
● Q = source charge (C)
● q = test charge (C)
● F = force on test charge (N)
● r = distance (m)
3. Electric Potential Energy (point charge)
𝑞1𝑞2
𝑈 = 𝐾 2
𝑟
U = potential energy (J)
4. Electric Potential (voltage)
𝑄
𝑉 = 𝑈𝑞 = 𝐾 𝑟
● V = electric potential (V)
5. Relation between Electric Field & Potential
, ∆𝑣
𝐸 =− ∆𝑑
● ΔV\Delta V = change in potential (V)
● Δd\Delta d = distance (m)
2. Current & Resistance
6. Definition of Current
𝑄
𝐼 = 𝑡
● I = current (A)
● Q = charge (C)
● T = time (s)
7. O hm’s Law
𝑉 = 𝐼𝑅
● V = voltage (V)
● I = current (A)
● R = resistance (Ω)
8. R
esistance of a Material
𝐿
𝑅 = ρ 𝐴
● ρ\rho = resistivity (Ω·m)
● L = length (m)
● A= cross-sectional area (m²)
3. Circuits (Series & Parallel)
9. R
esistors in Series
𝑅𝑒𝑞 = 𝑅1 + 𝑅2 +..... 𝑅𝑛
9 2 2
𝑘 is Coulombs Constant(8. 99 · 10 𝑁𝑚 /𝐶 )
1. Electrostatics
1. Coulomb’s Law
𝑞1𝑞2
𝐹𝑒 = 𝑘 2
𝑟
● 𝐹𝑒 is the electric force
Q
● are the charges on the two objects
● r is the distance between the two objects
2. E
lectric Field (point charge)
𝐹 𝑄
𝐸 = 𝑞 = 𝑘 2
𝑟
● E = electric field (N/C)
● Q = source charge (C)
● q = test charge (C)
● F = force on test charge (N)
● r = distance (m)
3. Electric Potential Energy (point charge)
𝑞1𝑞2
𝑈 = 𝐾 2
𝑟
U = potential energy (J)
4. Electric Potential (voltage)
𝑄
𝑉 = 𝑈𝑞 = 𝐾 𝑟
● V = electric potential (V)
5. Relation between Electric Field & Potential
, ∆𝑣
𝐸 =− ∆𝑑
● ΔV\Delta V = change in potential (V)
● Δd\Delta d = distance (m)
2. Current & Resistance
6. Definition of Current
𝑄
𝐼 = 𝑡
● I = current (A)
● Q = charge (C)
● T = time (s)
7. O hm’s Law
𝑉 = 𝐼𝑅
● V = voltage (V)
● I = current (A)
● R = resistance (Ω)
8. R
esistance of a Material
𝐿
𝑅 = ρ 𝐴
● ρ\rho = resistivity (Ω·m)
● L = length (m)
● A= cross-sectional area (m²)
3. Circuits (Series & Parallel)
9. R
esistors in Series
𝑅𝑒𝑞 = 𝑅1 + 𝑅2 +..... 𝑅𝑛
