RRB NTPC Electricity & Magnetism

• Unit conversions (kWh to Joules) • Ohm's law applications • Power calculations in household appliances • Fleming's rules for motor/generator direction • Magnetic field direction around current-carrying conductors Shortcut for Power Calculations: For household appliances, remember: Higher wattage = Higher power consumption = Higher electricity bill

kWh = kW × hours. Energy is what you pay for in electricity bills, not power. Always convert watts to kilowatts by dividing by 1000 when calculating electricity costs

• Electric motor converts electrical energy to mechanical energy • Generator converts mechanical energy to electrical energy • Transformer changes voltage levels using electromagnetic induction • Electromagnets are used in speakers, MRI machines, and cranes Safety in Electricity: Earth wire (green) provides safety path for leakage current. Fuses and circuit breakers protect against overload. Never touch electrical appliances with wet hands as water conducts electricity.