Question

Briefly explain the mechanism in Franklin's bells

Answer 1

Answer : Franklin's Bells mechanism

Franklins bell is a device which adopts the principle of charge transfer in static electricity. In static electricity, charging can be done , either by conduction or by induction.

Charging by conduction :- In this case ,a charged body when comes in physical contact with an uncharged body, the uncharged body will get the same charge as that of the charged one and the charged one will become neutral due to the transfer of electrons from one body to the another.

For example , a body A is charged positively and when it comes in physical contact with another body B which is neutral, the electrons from B flows to A , so that it will get neutralised. But due to the loss of electrons from B, it will become positvely charged. ( all these transfers are possible only if the electrons are loosely bound to the nucleus )

Carging by induction :- In this case a charged body when it is brought very near to an uncharged body, it will get charged in opposite polarity to that of the charged body. This is due to the fact that like charges will repel and unlike charges attract

Example. Body A is charged negativelyand when it is brought very near to the uncharged body, it attracts all positive charges of the uncharged body to the near end and repel the like charges to the farther end. so the farther end is now negatively charged. If this end is earthed, negative charges flow to the ground and by disconnecting, the body B becomes positively charged.

In franklin bell, there are two bells and a metallic gong or one another bell hanged in minimal distance from a conducting rod which is erected on an insulating stand One extreme bellis  hanged by conducting chain and the middle bell or gong and the other bell by a non conducting wire and this  extreme bell is earthed also

Working : Initially all the apparatus is electrically neutral. Now bring a negatively charged tefflon rod near to the one end of the conducting rod. By induction , the near end will become positively charged and the farther end to which one of the bell hanged by conducting wire ill get negative charge. Due to this , the gong or the middle bell, the nearby side becomes positively charged and thereby it will get attracted toards the negatively charged bell . When they comes in contact, the bell rings and at the same time the negative charges from the bell flows to the positive side of the gong and it will neutralise all the positve charges. Thus the gong becomes negatively charged. Now due to the repulsive force , it got repelled and hit on to the other extreme ball and give s a bell. At the same time , as this bell is earthed, all the negative charges got discharged to the ground and thereby the gong again becomes neutral. Now due to gravity it comes bac and hit on to the first bell and the process ill get repeated.

Figures are as follows

In franlins bell . electrical energy is converted to mechanical energy