Saved Bookmarks
| 1. |
(a) State Kirchhoff's rules for an electric network. Using Krichhoff's rules, obtain the balance condition in terms of the resistances of four arms of Wheatstone bridge,(b) In the meterbridge experimental set up, shown inthe Fig., the null point 'D' is obtained at a distance of 40 cm from end A of the meterbridge wire. If a resistance of 10Omegais connected in series with R_1, null point is obtained at AD = 60 cm. Calculate the values of R_1 and R_2 |
|
Answer» Solution :(b) As per question `R_1/R_2 = (40)/((100 - 40)) = 40/60 = 2/3` ` RARR R_2 = 3/2 R_1` Again on joining a RESISTANCE of `10 OMEGA` in series with `R_1` , we have ` rArr (R_1 + 10)/(R_2) = (60)/((100 - 60)) = 60/40 = 3/2` ` rArr R_2= 2/3 (R_1 + 10)` Comparing (i)and (ii) , we get ` 3/2 r_1 = 2/3 (R_1 + 10) rArr r_1 = 8 Omega` ` therefore R_2 = 3/2 R_1 = 3/2 xx 8 = 12 Omega` |
|