Capacitance of a capacitor made by a thin metal foil is 2 μ F. If the foil is folded with paper of thickness 0.15 mm, dielectric constant of paper is 2.5 and width of paper is 400 mm, the length of foil will be

Question

Capacitance of a capacitor made by a thin metal foil is 2 μ F. If the foil is folded with paper of thickness 0.15 mm, dielectric constant of paper is 2.5 and width of paper is 400 mm, the length of foil will be (A) 0.34 m (B) 1.33 m (C) 13.4 m (D) 33.9 m

Tardigrade Admin · Accepted Answer

Here, let the length be 1 width is, b =400 mm =0.4 m thickness, t =0.15 mm =15 × 10-5 m As capacitance for parallel plate capacitor is, C = K ϵ0 A / d = K ϵ0( l × b ) / t ⇒ l = Ct / K ϵ0 b =2 × 10-6 × 15 × 10-5 /(2.5 × 8.85 × 10-12 × 0.4) =33.91 m

Q. Capacitance of a capacitor made by a thin metal foil is 2μF. If the foil is folded with paper of thickness 0.15mm, dielectric constant of paper is 2.5 and width of paper is 400mm, the length of foil will be

0.34 m

1.33 m

13.4 m

33.9 m

Here, let the length be 1 width is, b=400mm=0.4m thickness, t=0.15mm=15×10−5m As capacitance for parallel plate capacitor is, C=Kϵ0​A/d=Kϵ0​(l×b)/t ⇒l=Ct/Kϵ0​b =2×10−6×15×10−5/(2.5×8.85×10−12×0.4) =33.91m

Q. Capacitance of a capacitor made by a thin metal foil is $2 μ F$ . If the foil is folded with paper of thickness $0.15 mm$ , dielectric constant of paper is $2.5$ and width of paper is $400 mm$ , the length of foil will be