Why things conduct electricity
3 marks · NormalA student wants to test the conductivity of three substances: solid calcium chloride, molten calcium chloride, and pure water.
For each substance, she sets up a circuit and measures the current flowing when a voltage of 6 V is applied.
| Substance | Current (A) |
|---|---|
| Solid calcium chloride | 0.00 |
| Molten calcium chloride | 1.45 |
| Pure water | 0.00 |
Calculate the total current measured for the substances that conduct electricity. Show your working.
Work this out on paper, then compare with the answer and worked solution below. With a free account you can submit written answers for marking.
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1.45 A (±0.01)
Common mistakes: Adding 0.00 values; Incorrectly including pure water
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Marking points
M1 · 1 mark · Identifies which substances conduct electricity (molten CaCl2 only).
M2 · 1 mark · Selects only the correct current values to add (1.45 A only).
A1 · 1 mark · States final total current as 1.45 A.
Worked solution
Only molten calcium chloride conducts electricity.
The current for conducting substances is: 1.45 A.
Total current measured is 1.45 A.