Kajunbee
Advanced Member level 1
This is one of Faradays experiments that Joseph Henry replicated. Faraday said that interposing a plate of copper or zinc did not show any shielding effect, But Henry’s experiments showed to the contrary. Can anyone see a reason why interposing a zinc plate would not deflect the galvanometer, yet the needle inside the magnetizing spiral is strongly magnetized. If I’m understanding the setup correctly current is induced in both secondary, but current is in opposition in galvanometer. Also the magnetizing spiral consist of two coils which I’m only assuming are opposing.
The main difference between Faraday and Henry’s experiments was that Faraday relied on motion. I believe he was raising and lowering battery plates. Whereas Henry was using mercury to deliver current to his coils. Applying full battery voltage instead increasing slowly.
I realize the wording is difficult to follow. This is the setup to the best of my knowledge.
Drawing.
I did not include it in drawing but there would be a zinc plate between the primary and one of the secondary’s. If there was shielding this would cause and imbalance and deflection on galvanometer. If I understand the setup correctly current flows through spiral and galvanometer in opposition. I can’t think of any scenario where the needle gets magnetized but no deflection of galvanometer.
I’m not sure if this is a clue, but I believe someone might be able to answer. In the previous paragraph 46 he says that if the body is placed in the circuit that zinc plate will almost completely neutralize the shocks. Notice he says almost, not completely. But if the galvanometer is placed across the secondary there is no screening effect. So it seems to be related to the resistance or impedance of the load.
The experiment on page 46 was a different setup than one in drawing. There was only one primary and secondary.
The main difference between Faraday and Henry’s experiments was that Faraday relied on motion. I believe he was raising and lowering battery plates. Whereas Henry was using mercury to deliver current to his coils. Applying full battery voltage instead increasing slowly.
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I realize the wording is difficult to follow. This is the setup to the best of my knowledge.
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Drawing.
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I did not include it in drawing but there would be a zinc plate between the primary and one of the secondary’s. If there was shielding this would cause and imbalance and deflection on galvanometer. If I understand the setup correctly current flows through spiral and galvanometer in opposition. I can’t think of any scenario where the needle gets magnetized but no deflection of galvanometer.
--- Updated ---
I’m not sure if this is a clue, but I believe someone might be able to answer. In the previous paragraph 46 he says that if the body is placed in the circuit that zinc plate will almost completely neutralize the shocks. Notice he says almost, not completely. But if the galvanometer is placed across the secondary there is no screening effect. So it seems to be related to the resistance or impedance of the load.
--- Updated ---
The experiment on page 46 was a different setup than one in drawing. There was only one primary and secondary.
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