Electricity — Complete NCERT Lesson
? Electric Charge and Current
Electric current is the flow of electric charges (electrons) through a conductor. Current is measured in Amperes (A) using an ammeter.
?? Electric Potential and Potential Difference
Potential difference (V) is the work done per unit charge to move a charge from one point to another. Measured in Volts (V) using a voltmeter.
?? Ohm's Law
At constant temperature: V ? I, so V = IR
?? Series and Parallel Circuits
| Property | Series | Parallel |
|---|---|---|
| Current | Same through all | Different in each branch |
| Voltage | Divides across resistors | Same across each branch |
| Total Resistance | R = R1+R2+R3... | 1/R = 1/R1+1/R2+1/R3 |
| If one bulb fuses | All go off | Others still work |
?? Heating Effect of Electric Current
When current flows through a resistor, electrical energy converts to heat. This is described by Joule's Law:
Applications: electric heater, electric iron, toaster, fuse wire.
Electricity — MCQ Practice
Electricity — Mnemonic
Mnemonic 1: For Ohm’s Law (V = IR)
“Very Intelligent Ram” ⚡️
- V = Voltage (Potential Difference)
- I = Current
- R = Resistance
Remember: Voltage = Current × Resistance
Mnemonic 2: Series Circuit Characteristics
“Single Chain, Current Same” 🔗
- Series circuit means one path
- Current is same everywhere
- Cumulative voltage (sum of voltages)
- Sum of resistances adds up
Hindi rhyme: "Ek hi raah, current saath, voltage jode, resistance baadh"
Mnemonic 3: For Electric Power Formula (P = VI)
“Power Vampire Is” 🧛♂️⚡️
- P = Power (in Watts)
- V = Voltage (Volts)
- I = Current (Amperes)
Think: Power is the vampire that drinks Voltage and Current!
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