In an unloaded transformer, the fluxes limiting the primary and secondary are 25 mwb and 15 mwb. The coefficient of coupling

• A. cannot be calculated
• B. <table><tr> <td rowspan="2"> </td> <td style="border-bottom:1px solid #000000;vertical-align:bottom;padding-bottom:2px;"><center>5</center></td><td rowspan="2"></td></tr><td align="center">3</td></table>
• C.
• D. <table><tr> <td rowspan="2"> </td> <td style="border-bottom:1px solid #000000;vertical-align:bottom;padding-bottom:2px;"><center>3</center></td><td rowspan="2"></td></tr><td align="center">5</td></table>
• E. 25: 15