Saved Bookmarks
| 1. |
Define current sensitivity and voltage sensitivity of a galvanometer. Increasing the current sensitivity may not necessarily increase the voltage sensitivity of a galvanometer. Justify. |
|
Answer» Solution :The current sensitivity of a galvanometer is defined as the deflection per unit current. `:.` Current sensitivity `phi/I = (NAB)/(k)`, where`k`= restoring torque per unit deflection. The voltage sensitivity of a galvanometer is defined as the deflection per unit voltage. `:.` Voltage sensitivity `phi/V = (NAB)/k cdot 1/R`, where R is the resistance of the galvanometer. Increase in current sensitivity may not NECESSARILY increase the voltage sensitivity. To explain it let US double the number of turns N of galvanometer coil. So as to double the current sensitivity. However, on doubling the number of turns the resistance of galvanometer coil is also doubled from R to 2R consequently voltage sensitivity REMAINS unchanged. |
|