A light bulb and an open coil inductor are connected in series to an A.C source through a key .The Key is closed and after sometime iron rod is inserted into the interior of inducror . The glow of light bulb...(a)Increase (b) Decreases (c) Uncharged
WHEN rod is inserted what will be your answer if ac is replaced by dc .How the glow of bulb of change if the no of turns of coil is reduced.
- As the iron rod is inserted, the magnetic field inside the coil magnetizes the iron increasing the magnetic field inside it. Hence, the inductance of the coil increases. Consequently, the inductive reactance of the coil increases. As a result, a larger fraction of the applied ac voltage appears across the inductor, leaving less voltage across the bulb. Therefore, the glow of the light bulb decreases.
- In case of dc source the brightness of the bulb remains unchanged as the reactance offered by a coil to a d.c. current is zero.
- Reduced;A bulb connected to the coil with the more number of turns lights up brighter while the bulb that is connected to the coil with fewer number of turns is dimmer.