A) \[9:5\]
B) \[5:9\]
C) \[5:4\]
D) \[4:5\]
Correct Answer: D
Solution :
Key Idea: In a transformer Power in primary=Power in secondary. If \[{{i}_{p}}\] and \[{{i}_{s}}\] be the currents in the primary and secondary at any instant and the energy losses be zero, then Power in secondary = Power in primary \[{{v}_{s}}\times {{i}_{s}}={{V}_{P}}\times {{i}_{P}}\] \[\Rightarrow \] \[\frac{{{i}_{p}}}{{{i}_{s}}}=\frac{{{V}_{s}}}{{{V}_{p}}}=\frac{{{N}_{s}}}{{{N}_{p}}}=r=\]Transformer ratio Given, \[{{N}_{p}}=5,\,\,{{N}_{s}}=4,\,\,{{V}_{p}}=220\,V\] \[\therefore \] \[\frac{{{i}_{p}}}{{{i}_{s}}}=\frac{{{N}_{s}}}{{{N}_{p}}}=\frac{4}{5}\] \[\Rightarrow \] \[{{i}_{p}}:{{i}_{s}}=4:5\] Note: Since number of turns is secondary is less than that in primary, hence it is a step-down transformer.
You need to login to perform this action.
You will be redirected in
3 sec
