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AQA GCSE · Question 03.3 · Electricity
The student used a cell that had a potential difference of 1.50 V.
Explain why the cell was not an electrical hazard to the student in the investigation.
The student used a cell that had a potential difference of 1.50 V.
Explain why the cell was not an electrical hazard to the student in the investigation.
How to approach this question
1. State whether 1.50 V is a high or low potential difference.
2. Relate the potential difference and the body's resistance to the size of the current that would flow through the student.
3. Explain why this size of current is not hazardous.
Full Answer
The potential difference of 1.50 V is very low. This low voltage is not high enough to push a significant or dangerous current through the high resistance of the human body.
An electric shock occurs when a current flows through the human body. The size of this current is determined by Ohm's Law (I = V/R), where V is the potential difference and R is the resistance of the body. The human body has a very high electrical resistance. A potential difference of 1.50 V is very low and is therefore insufficient to drive a current large enough to pass through the body's high resistance and cause harm or even be felt.
Common mistakes
✗ Just saying "the voltage is too low" without explaining the link to current and resistance.
✗ Confusing voltage and current, for example, saying "the current is too low" without mentioning voltage.
Practice the full AQA GCSE Physics Higher Tier Paper 1
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