Physics Electricity Formulas - Science Class 10

Learn important formulas from the Physics Electricity chapter of Class 10 Science with examples, variables and applications.

📐 Physics Electricity Formulas

Complete collection of formulas with explanations and examples

Commercial Unit of Energy

$$1 kWh = 3.6 x 10^6 J$$

Description: Commercial Unit of Energy is a standard relation used in physics-electricity.

Example:

Apply the relation: 1 kWh = 3.6 x 10^6 J

Identify the known values, substitute them in the relation, and solve for the unknown quantity.
Result depends on the substituted values.

Applications:

  • Use this when the quantities in the relation are known and the missing quantity is required.

Electric Current

$$I = Q/t$$

Description: Electric Current is a standard relation used in physics-electricity.

Example:

Apply the relation: I = Q/t

Identify the known values, substitute them in the relation, and solve for the unknown quantity.
Result depends on the substituted values.

Applications:

  • Use this when the quantities in the relation are known and the missing quantity is required.

Electric Power

$$P = VI = I^2R = V^2/R$$

Description: Electric Power is a standard relation used in physics-electricity.

Example:

Apply the relation: P = VI = I^2R = V^2/R

Identify the known values, substitute them in the relation, and solve for the unknown quantity.
Result depends on the substituted values.

Applications:

  • Use this when the quantities in the relation are known and the missing quantity is required.

Joule Heating

$$H = I^2Rt$$

Description: Joule Heating is a standard relation used in physics-electricity.

Example:

Apply the relation: H = I^2Rt

Identify the known values, substitute them in the relation, and solve for the unknown quantity.
Result depends on the substituted values.

Applications:

  • Use this when the quantities in the relation are known and the missing quantity is required.

Ohm Law

$$V = IR$$

Description: Ohm Law is a standard relation used in physics-electricity.

Example:

Apply the relation: V = IR

Identify the known values, substitute them in the relation, and solve for the unknown quantity.
Result depends on the substituted values.

Applications:

  • Use this when the quantities in the relation are known and the missing quantity is required.
  • Exam relevance: ssc, railway, neet

Parallel Resistance

$$1/R_p = 1/R1 + 1/R2 + 1/R3$$

Description: Parallel Resistance is a standard relation used in physics-electricity.

Example:

Apply the relation: 1/R_p = 1/R1 + 1/R2 + 1/R3

Identify the known values, substitute them in the relation, and solve for the unknown quantity.
Result depends on the substituted values.

Applications:

  • Use this when the quantities in the relation are known and the missing quantity is required.

Potential Difference

$$V = W/Q$$

Description: Potential Difference is a standard relation used in physics-electricity.

Example:

Apply the relation: V = W/Q

Identify the known values, substitute them in the relation, and solve for the unknown quantity.
Result depends on the substituted values.

Applications:

  • Use this when the quantities in the relation are known and the missing quantity is required.

Resistance from Resistivity

$$R = rho l/A$$

Description: Resistance from Resistivity is a standard relation used in physics-electricity.

Example:

Apply the relation: R = rho l/A

Identify the known values, substitute them in the relation, and solve for the unknown quantity.
Result depends on the substituted values.

Applications:

  • Use this when the quantities in the relation are known and the missing quantity is required.

Series Resistance

$$R_s = R1 + R2 + R3$$

Description: Series Resistance is a standard relation used in physics-electricity.

Example:

Apply the relation: R_s = R1 + R2 + R3

Identify the known values, substitute them in the relation, and solve for the unknown quantity.
Result depends on the substituted values.

Applications:

  • Use this when the quantities in the relation are known and the missing quantity is required.

Quick Reference

Commercial Unit of Energy: $1 kWh = 3.6 x 10^6 J$
Electric Current: $I = Q/t$
Electric Power: $P = VI = I^2R = V^2/R$
Joule Heating: $H = I^2Rt$
Ohm Law: $V = IR$
Parallel Resistance: $1/R_p = 1/R1 + 1/R2 + 1/R3$
Potential Difference: $V = W/Q$
Resistance from Resistivity: $R = rho l/A$
Series Resistance: $R_s = R1 + R2 + R3$

💡 Worked Examples

Step-by-step solutions using Physics Electricity formulas

Example 1: Area of Circle

Circle Area Formula
Problem:

Find the area of a circle with radius 7 cm.

Solution:
  1. Given: r = 7 cm
  2. Apply formula: A = πr²
  3. Substitute: A = π × 7²
  4. Calculate: A = π × 49 = 49π cm²
  5. Approximate: A ≈ 49 × 3.14159 ≈ 153.94 cm²
Answer:

Area = 49π cm² ≈ 153.94 cm²

🎯 Practice Problems

Try these problems to test your understanding:

Practice Problem 1

Solve the quadratic equation: x² - 7x + 12 = 0

Practice Problem 2

Find the area of a circle with diameter 14 cm.

Practice Problems

Check Your Formula Recall

Write each formula once, define every variable, then solve one direct substitution problem before moving to mixed questions.

Apply Physics Electricity

Pick two formulas from this page and create your own values for the variables. Verify units and signs before calculating.

Derivation Notes

Focus on how the formula is built, not only the final expression. Derivations help with board-exam reasoning and multi-step application questions.

  • Start from the definition or identity used in the chapter.
  • Write assumptions clearly before substituting values.
  • Track units through each step to catch calculation mistakes.

Where These Formulas Are Used

Board Exam Problems

Use these formulas for direct numerical questions, proof-based steps, and short-answer reasoning in Science.

Competitive Practice

Memorize the condition of use for each formula so you can identify the right expression quickly under timed practice.

Related Formula Chapters

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These Physics Electricity formulas help students revise concepts quickly and apply equations accurately in exam-style problems.

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