1
\mathrm{Q}=\mathrm{n}\mathrm{e}
2
\mathrm{I}=\frac{\mathrm{Q}}{\mathrm{t}}
3
\mathrm{V}=\frac{\mathrm{W}}{\mathrm{Q}}
4
\mathrm{V}_{1}-\mathrm{V}_{2}=\frac{\mathrm{W}}{\mathrm{Q}}
5
\mathrm{V}=\mathrm{I}\mathrm{R}
FORMULA CHAPTER
Chapter 09 – Current Electricity
ICSEClass 09Physics5 formulas
Complete ICSE Class 9 Chapter 09 formulas for electric charge, current, potential difference, resistance, Ohm’s law, electrical work and power.
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Electric Charge from Number of Electrons
\mathrm{Q}=\mathrm{n}\mathrm{e}
Worked example
Given: n = 2 × 10¹⁹ Calculation: Q = n × e Answer: Q = 3.2 C
Electric Current
\mathrm{I}=\frac{\mathrm{Q}}{\mathrm{t}}
Worked example
Given: Q = 10 C, t = 2 s Calculation: I = 10/2 Answer: I = 5 A
Electric Potential
\mathrm{V}=\frac{\mathrm{W}}{\mathrm{Q}}
Worked example
Given: W = 20 J, Q = 4 C Calculation: V = 20/4 Answer: V = 5 V
Potential Difference
\mathrm{V}_{1}-\mathrm{V}_{2}=\frac{\mathrm{W}}{\mathrm{Q}}
Worked example
Given: W = 12 J, Q = 3 C Calculation: V1 − V2 = 12/3 Answer: Potential difference = 4 V
Ohm’s Law
\mathrm{V}=\mathrm{I}\mathrm{R}
Worked example
Given: I = 2 A, R = 5 ohm Calculation: V = 2 × 5 Answer: V = 10 V