A. Discharge lamps
B. Incandescent lamps
C. Arc lamps
D. Induction furnaces
Answer: B. Incandescent lamps
Explanation:
An incandescent lamp is a coiled tungsten filament lamp.
Incandescent lamps produce light as a result of the heating effect of an electrical current flowing through a filament wire
As it is a highly resistive circuit, the power factor of an incandescent lamp is very high and ideally, it is unity.
Causes of low power factor:
Most of the AC motors are of induction type (1φ and 3φ induction motors) which have a low lagging power factor
These motors work at a power factor which is extremely small on light load (0.2 to 0.3) and rises to 0.8 or 0.9 at full load.
Arc lamps, electric discharge lamps and industrial heating furnaces operate at a low lagging power factor.
The load on the power system is varying; being high during morning and evening and low at other times.
During low load period, the supply voltage is increased which increases the magnetization current, this results in the decreased power factor.
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