Learn Unit IV: Effects of Current with Free Lessons & Tips

To calculate the energy consumed by the electric bulbs in the month of February, first, we calculate the energy consumed by the 250-watt bulb and the four 6-watt bulbs separately. Then, we sum up the total energy consumed. Energy consumed by the 250-watt bulb in 5 hours = 250×5/1000 kWh Energy consumed by each 6-watt bulb in 4.5 hours = 6×4.5×4/1000 kWh Total energy consumed in the month of February = Energy consumed by the 250-watt bulb + Energy consumed by the four 6-watt bulbs

Joule's law states that the heat produced in a resistor is directly proportional to the square of the current passing through it and the resistance of the resistor. Mathematically, H=I²×R, where H is the heat produced, I is the current, and R is the resistance. To find the current, I=P/V and then use Ohm's law to find resistance R=V/I

• A fuse is placed in series with an electrical appliance in a circuit to protect the appliance and the circuit from damage due to excessive current. A fuse with a defined rating should not be replaced by one with a larger rating because a larger-rated fuse may allow too much current to pass through the circuit, risking damage to the appliance and causing a potential fire hazard.

• The frequency of an alternating current (AC) is the number of complete cycles per second and is measured in hertz (Hz). In India, the standard frequency of AC power supply is 50 Hz. Alternating current is considered advantageous over direct current (DC) for long-range transmission of electric energy because it can be easily stepped up or down in voltage using transformers, which allows for efficient transmission over long distances with minimal energy loss.

• An electromagnet is a type of magnet in which the magnetic field is produced by the flow of electric current. To transform a soft iron piece into an electromagnet, a coil of wire is wound around the iron core, and when electric current passes through the coil, it magnetizes the iron core, creating a temporary magnet.

• Induced current in a circuit can be generated by electromagnetic induction, which occurs when a change in magnetic flux through a closed circuit induces an electromotive force (emf) that causes current to flow. This can be achieved by moving a magnet near a coil of wire or by changing the magnetic field strength through the coil.