Problem 189: A 6.0 H coil whose resistance is 12 ohms is connected in series with a 24 ohms resistor and to a 144 V battery and a switch. The switch is closed at t = 0. Determine the energy stored in the magnetic field at steady state.
A50 J
B48 J
C52 J
D46 J
#22
Problem 190: Two coils having self-inductance and mutual inductance of 3H, 2H and 1H respectively are connected in series. If a current of 4 A is passed through the coil, evaluate the ratio of the energy stored in the magnetic field when the fluxes (self and mutual) are in the same direction to the energy stored when the said fluxes are against each other.
A3.24
B2.33
C1.73
D2.67
#23📜 EE Board April 1995
Problem 191: Two coils of inductances 4 and 6 henry are connected in parallel. If their mutual inductance is 3 henry, calculate the equivalent inductance of the combination if mutual inductance assist and if mutual inductance opposes the self-inductance respectively.
A2.4 H & 1.4 H
B3.75 H & 0.94 H
C6.25 H & 2.75 H
D16 H & 4 H
#24
Problem 192: A 50-mH inductor is charged to store 1 J of energy. If an uncharged 30-mH inductor is then connected across its terminals, how much energy is transferred to the second inductor?
A0.154 J
B0.262 J
C0.234 J
D0.141 J
#25
Problem 193: A solenoid 500 cm long and 10 cm in diameter is wound with 1500 turns. Find the energy stored in the magnetic field when a current of 5 A flows.
A0.45 J
B0.55 J
C0.46 J
D0.72 J
#26
Problem 194: A coil of 250 turns is wound on a closed iron ring whose cross sectional area is \(20\,cm^2\) and mean length of 100 cm. Determine the energy stored in the magnetic field if a current of 2 A is passed through it. Assume the permeability of iron is 900.
