NEET-XII-Physics
31: Capacitors
- #18-aCalculate the capacitance. (b) Another capacitor of the same length is constructed with cylinders of radii 4 mm and 8 mm. Calculate the capacitance. (b) Another capacitor of the same length is constructed with cylinders of radii 4 mm and 8 mm. Calculate the capacitance.Ans : The capacitance of a cylindrical capacitor is given by
`` C=\frac{2\,\mathrm{\,\pi \,}{\in }_{0}l}{\,\mathrm{\,ln\,}\left({\displaystyle \frac{{R}_{2}}{{R}_{1}}}\right)}``
`` \Rightarrow C=\frac{2\times 3.14\times 8.85\times {10}^{-12}\times 0.10}{\,\mathrm{\,ln\,}2}``
`` \Rightarrow C=8\,\mathrm{\,pF\,}\left(\because \,\mathrm{\,l\,}\,\mathrm{\,n\,}2=0.693\right)`` (b) When a capacitor of the same height with cylinders of radii 4 mm and 8 mm is taken, its capacitance comes to 8 pF, which is the same as above because the ratio of the radii is the same.
Page No 166: (b) When a capacitor of the same height with cylinders of radii 4 mm and 8 mm is taken, its capacitance comes to 8 pF, which is the same as above because the ratio of the radii is the same.
Page No 166:
- #18-bAnother capacitor of the same length is constructed with cylinders of radii 4 mm and 8 mm. Calculate the capacitance.Ans : When a capacitor of the same height with cylinders of radii 4 mm and 8 mm is taken, its capacitance comes to 8 pF, which is the same as above because the ratio of the radii is the same.
Page No 166: