Saved Bookmarks
| 1. |
A capacitor is an arrangement for storing large amounts of electriccharge and hence electric energy in a small space. The electrical capacitance of a capacitor is relatedto its abillity to storeelectriccharge. We definecapacity of a conductor as the ratio of charge Q givento the conductorto the rise in its potential,V i.e., C = Q//V. The capacity of an isoltedspherical conductor of radiusr is C = 4pi in_(0) r. In case of a parallel plate capacitor, C = (in_(0)A)/(d) where A is area of insulatedmetal plateand d is distance betweenthe plates. Clearly, capacitydepends on size of capacitor. When different capacitors are connectedin series, capacity, C_(s) = (C_(1) C_(2))/(C_(1) + C_(2)) and when capacitors are connected in parallel, C_(p) = C_(1) + C_(2) Read the above passage and answer the following questions : (i) From C = (Q)/(V), we find that C can beincreased Q or decresingV. Do youagree ? (ii) Capacity of a capacitor is fixeddependingon its geometry and the medium used. Is it true ? (iii) Calculatethe capacity of a condenser which when connected in series with a conductor of 12 muF gives us a capacitance of 3 muF. (iv) What values of lifedo yo+-earn from this study ? |
|
Answer» Solution :No, we do AGREE. This is becausecapacitanceC is fixed, dependingon geometry fo condeaser. If we increaseQ , Vincreases but C remainsconstant and vice-versa. (ii) yes, the statement is true. (iii) Here, `C_(1) = ? C_(2) = 12 MUF, C_(s) = 3 muF` From `C_(s) = (C_(1) C_(2))/(C_(1) + C_(2))` `3 = (C_(1) xx 12)/(C_(1) + 12) or 12C_(1) = 3C_(1) + 36 C_(1) = 4muF` (iv) Just as capacity fo a condenser is fixeddependingon its geometry, similarly capacity of a person to execuitesome workis fixeddependingon his buit up. Capacity increases by connectingthe CAPACITORS in parallel. exactly in the same way capacity of a group of persons can be increased wheneach ONEOF themis connectedto the same sources , e.g., guideor instractor. This is the implication of this concept in day to day life. |
|