Electric Current> An electric lamp is connected in series w...

An electric lamp is connected in series with a long solenoid of copper with air core. When the circuit is joined to AC source, the bulb lights up giving a bright glow. Now an iron rod is inserted inside the solenoid, the brightness of the bulb,increases or decreases????

VIDYARANI SINGADI , 7 Years ago

Grade 12th pass

2 Answers

Vikas TU

The brightness will be increased as the core now would be acting as a strong conductor and will now behave as a permanent magnet hence the magnetic field lines increases and hence emf increases and current increases. This leads to increase in the brightness of the bulb.

Approved

Last Activity: 7 Years ago

Prabhjot

When the iron rod is inserted in the solenoid, the bulb will dim. It's brightness will decrease.

As rod is inserted, magnetic field inside the solenoid increases. And I is indirectly proportional to this. Therefore I will decrese and bulb will glow dimmer.

Also the solenoid will now intake more I (current). Thus the bulb will get less current and it's brightness will DECREASE.

Last Activity: 6 Years ago