a solenoid of inductance 250mH and resistance 10ohm is
connected to a battery. the time taken for the magnetic energy
to reach 1/4th of its maximum value will be?



a solenoid of inductance 250mH and resistance 10ohm is connected to a battery. the time taken for ..

Answer / 7anoter4

Magnetic energy is W=B*H =miuo*H^2=K*i^2
Wmax=K*Imax^2 ΒΌ*Wmax=K*Imax^2/4 i=Imax/2
The current equation it is: i=Imax*[1-e^(-t*L/R)] . If
i=1/2*Imax then : e^(-t*L/R)=1/2 and t=-LN(1/2)*R/L R=10
ohm L=0.250 H t=27.73 sec.

Is This Answer Correct ?    0 Yes 3 No

Post New Answer

More Electrical Engineering Interview Questions

what is cable meggering formula for low voltage ?

0 Answers  


Why PT is fitted in incomer panel.....?

1 Answers  


how to calculate current when LT supply 415v fed to HT Motor 6.6kv and 1120kw.

2 Answers  


why dc series moter is not started at no load?

5 Answers   IOCL,


How do you protect your appliances from harm in case of neutral failure in a three phase power supply set up.

4 Answers  






why, when birds sit on transmission lines or current wires doesn't get shock?

36 Answers   College School Exams Tests, Infosys,


What type of pipe material G.I or M.S is used for sprinkler system?

2 Answers  


HOW TO CONNECT THREE PHASE OVER LOAD RELAY FOR SINGLE PHASE

2 Answers   Quest,


What is the function of earthfault relay?

18 Answers   MultiTech, Tech Mahindra,


what is the Earth Voltages in Power Plants, Sub-stations, Industries, Residential & Commercial Buildings.

0 Answers   Power Grid,


Why we use 2core cable for Dc motor.Can I use 3core?

5 Answers   JK Paper, Maharaja Whiteline,


Define unilateral circuit?

0 Answers  


Categories
  • Civil Engineering Interview Questions Civil Engineering (5085)
  • Mechanical Engineering Interview Questions Mechanical Engineering (4451)
  • Electrical Engineering Interview Questions Electrical Engineering (16632)
  • Electronics Communications Interview Questions Electronics Communications (3918)
  • Chemical Engineering Interview Questions Chemical Engineering (1095)
  • Aeronautical Engineering Interview Questions Aeronautical Engineering (239)
  • Bio Engineering Interview Questions Bio Engineering (96)
  • Metallurgy Interview Questions Metallurgy (361)
  • Industrial Engineering Interview Questions Industrial Engineering (259)
  • Instrumentation Interview Questions Instrumentation (3014)
  • Automobile Engineering Interview Questions Automobile Engineering (332)
  • Mechatronics Engineering Interview Questions Mechatronics Engineering (97)
  • Marine Engineering Interview Questions Marine Engineering (124)
  • Power Plant Engineering Interview Questions Power Plant Engineering (172)
  • Textile Engineering Interview Questions Textile Engineering (575)
  • Production Engineering Interview Questions Production Engineering (25)
  • Satellite Systems Engineering Interview Questions Satellite Systems Engineering (106)
  • Engineering AllOther Interview Questions Engineering AllOther (1379)