Practice portal › Electric Potential and Capacitance › Capacitance and Dielectrics

In a parallel plate capacitor of capacitance 1 μF, the intervening medium between the plates is vacuum. The area of the plates is 10⁻² cm². What is the distance between the two plates? (ε₀=8.85×10⁻¹² SI units)

Asked in GSEB Board July 2023 · Capacitance of a conductor and a capacitor

• (1) 8.85×10⁻⁹ m
• (2) 8.85×10⁻¹⁰ m
• (3) 8.85×10⁻⁶ m
• (4) 8.85×10⁻¹² m

Step-by-step solution

Why the other options are wrong

• (1) No single slip gives 8.85×10⁻⁹ m. Sanity check: d=(ε₀A)/C=(8.85×10⁻¹²×10⁻⁶)/(10⁻⁶)=8.85×10⁻¹² m.
• (2) Converts cm² to m² with 10⁻², the factor for a length, giving A=10⁻⁴ m². An area needs (10⁻²)²=10⁻⁴, so 10⁻² cm²=10⁻⁶ m².
• (3) Leaves the area out, i.e. d=(ε₀)/C. The plate area multiplies ε₀ in d=(ε₀A)/C.

Reading this solution needs no sign-in. You only sign in to practise against the clock and keep your progress.