‹ Back to the paper
The computer’s keyboards make use of capacitors at the base of their keys (as shown in the…
The computer’s keyboards make use of capacitors at the base of their keys (as shown in the diagram).
Each key is connected to a movable plate, which represents one side of the capacitor. The fixed plate on the keyboard's bottom represents the capacitor's other side. External electronic circuits recognize each key in its capacitance when pressed.
(a)
How would the capacitance of the capacitor so formed change, when the key is pressed?
(b)
If the plate area is $2\text{ cm}^2$ and the plate separation is 1 mm, calculate the charge density on the plate, if the potential difference between the plates is 3 V. The plates are separated by a dielectric of K = 5.
(c)
Sketch a graph showing the variation of electric field E between the plates with distance 'd' from the first plate till the second plate.
Answer
No answer yet.
From ISC 2025 Practice Physics, question 81.