MHT CET20243 May 2024Evening ShiftPhysicsAlternating CurrentActual
When 80 volt d.c. is applied across a solenoid, a current of 0.8 A flows in it. When 80 volt a.c. is applied across the same solenoid, the current becomes 0.4 A . If the frequency of a.c. source is 50 Hz , the impedance and inductance of the solenoid is nearly
Options
- A200 , 0.55 H
- B100 , 0.8 H
- C300 , 1.2 H
- D200 , 1.5 H
Correct answer
A. 200 , 0.55 H
Step-by-step solution
When 80 Vdc is applied, aligned Z & = R ^2+( L )^2 = R ( =0 in dc circuit ) Z & = R = V I = 80 0.8 =100 (i) aligned When 80 V ac is applied, aligned & Z= V I = 100 0.5 =200 ...(ii) & Z= R^2+( L)^2 & (2 fL )^2=Z^2-R^2 & L= 200^2-100^2 (2 50)^2 =0.55 H aligned ...[From(i).and (ii)]