Lead chloride crystals were placed in a basin. The accumulator was joint in series with the switch however when the switch was turned on the ammeter showed no deflection. When the lead chloride crystals were heated too 500 degrees celsius the ammeter showed a reading.Explain the above phenomenon.
I don't know what "accumulator was joint in series" means.
Lead Chloride is an ionic crystal, usually ionic crystals lock ions into place and they are at best semiconductors.
In liquid form, ions are free to move, and they are good conductors.
The melting point of PbCl2 is about 501 deg C. If the crystals melted, that would account for the increased conductivity. Impurities in the crystals could have lowered the melting point to 500 deg C. easily.
The phenomenon described can be explained by understanding the behavior of lead chloride crystals in the presence of an electric current and at different temperatures.
First, let's break down the given scenario:
1. "Lead chloride crystals were placed in a basin."
- This means lead chloride crystals were present in the basin.
2. "The accumulator was joint in series with the switch."
- The accumulator and the switch were connected in series, which means the current passes through both of them.
3. "When the switch was turned on, the ammeter showed no deflection."
- When the switch was activated, the ammeter, which measures electric current, did not show any movement or reading.
4. "When the lead chloride crystals were heated to 500 degrees Celsius, the ammeter showed a reading."
- But when the lead chloride crystals were heated to 500 degrees Celsius, the ammeter finally showed a reading or deflection.
Now, let's explain this phenomenon:
Lead chloride (PbCl2) is an ionic compound, consisting of positively charged lead ions (Pb2+) and negatively charged chloride ions (Cl-). In its solid state, meaning at room temperature and below, lead chloride does not conduct electricity efficiently because its ions are held in a fixed position and cannot move freely to carry an electric current.
When the switch is first turned on, there is no current flow through the circuit. This lack of movement of charge prevents the electric current from passing through the lead chloride crystals, resulting in no deflection on the ammeter.
However, when the lead chloride crystals are heated to a high temperature (500 degrees Celsius in this case), they undergo a physical change. At elevated temperatures, the lead chloride crystals start to melt and become a molten liquid. In this molten state, the ions are free to move and conduct electric charge.
Once the lead chloride crystals become molten, the electric current can flow through them. Consequently, the ammeter now shows a reading or deflection, indicating the presence of the electric current.
In summary, the lack of deflection in the ammeter when the switch is initially turned on is because lead chloride crystals, in their solid state, do not conduct electricity effectively. But when they are heated to a high temperature and become molten, the ions become free to move, allowing for the flow of electric current and resulting in a deflection in the ammeter.