A technician working in a microchip factory must wear a special wristband that connects them to the ground. Explain why wearing this wristband prevents damage to microchips caused by static electricity.

OCR GCSE Physics A: Gateway Science (J249) — P3.1 Static and charge · Explain · 4 marks · View as Markdown

Written & reviewed by James Millett — Biology (Imperial College London), PGCE Science (University of Cambridge).

Microchips can be destroyed by sudden discharges of static electricity. Workers handling microchips can build up a static charge on their bodies through friction as they move around the factory.

Model answer (4 marks)

Movement and friction transfer electrons to or from the worker’s body, creating a static charge.
The wristband is a conductor that connects the worker to the earth.
Any excess charge on the worker can then flow through the wristband into the ground, preventing a large potential difference.
Because no large charge remains, no sudden discharge or spark can occur, so the microchip is protected.

Examiner tips

  • Use the word ‘static charge’ and explain electron transfer; mention the wristband as a conductive path to earth; state that charge flows away, preventing a spark; link this to protection of the microchip.

Common mistakes

  • Failing to mention the wristband’s role as a conductive path; confusing static charge with current; not linking the absence of a spark to microchip safety.

Mark scheme (4 marks)

  1. Movement/friction causes electrons to transfer to or from the worker's body, building up a static charge
  2. The wristband provides a conducting path between the worker and the ground
  3. Charge continuously flows to earth so no large static charge builds up on the worker
  4. So there is no sudden discharge / spark that could transfer charge through the microchip and damage it

Key terms in this question

static electricity

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