A coil with a self-inductance of 9.6 H carries a current that varies with time according to I(t) (4.0 A)sin(2t). Find an expression for the emf induced in the coil. (Use the following as necessary: t. Assume & is in volts and t is in seconds. Do not include units in your answer.) E(t) Additional Materials Reading 0

a) We assume that the switch is on. Calculate the reactance values and find the charging current in the circuit below. Is the circuit capacitive or inductive? Show that the voltage across the capacitance can be slightly larger than the source voltage U. (This is called the Ferranti effect and means that we can get a voltage rise beyond overhead lines with small loads. This is mostly relevant at the highest voltage levels. The frequency f is 50Hz, and assume voltage U= √2⋅24kV

A steady current of 3.5 A is flowing through an inductor with 50 volts across it. Find (a) Inductance of the coil if the current falls to zero in 120 msec, (b) Energy stored in the inductor, (c) Number of turns in the inductor for a flux of 40 mWb. adows bu bolow and find the value of current flowind

A coil used for control applications is being supplied by a 24-V DC supply. When the coilis disconnected from the source using a switch, sparks occur at the switch. In an attemptto solve this problem, a 100 microfarad capacitor is connected in parallel to the coil. Ifthe coil has an inductance of 0.1 Henrys and a resistance of 20 Ohms, explain if theaddition of the capacitor helped solve the problem. Determine the voltage across theswitch to aid your explanation.

1. What impedance vector 0 – j22 represents:A. A pure resistance.B. A pure inductance.C. A pure capacitance.D. An inductance combined with a resistance.

Two coupled coils have self-inductances L1= 2 H and L2=0.5 H, and a coefficient of coupling K = . 0.9. Determine the turns ratio N1/N2 of the two coils. a. 2 b. 0.2 c. 0.5 d. 0.9

A. A coil of 1000 turns is uniformly wound on a ring of non-magnetic material, the mean diameter being 20 cm. The cross-sectional area of the coil is 4 cm2. Determine the selfinductance of the coil. Ans. 0.8mH B.An iron core 0.4m long and 5 cm2. In cross section, is wound with 300 turns. When a current of 0.5 A flows in the coil, how much is the inductance of the coil. Assume the core has a permeability of 2500.

An industrial coil has a resistance of 32 ohms and a reactance of 24 ohms and rated 440 volts at 60 Hz. A factory will connect the coil to a 440 V, 50 Hz supply. Solve for the value of a series resistor needed to avoid overcurrent condition.  Show complete solution.

A coil has a time constant of 1s and an inductance of 10 H.Find 1) the value of current 0. 1s after switching to a steady p.d.of 100 V (ii) the time taken for the current to reach halfits steady - state value.

A steady current of 3 A is flowing through an inductor with 60 volts across it. Find (a) Inductance of the coil if the current falls to zero in 200 msec, (b) Energy stored in the inductor, (c) Number of turns in the inductor for a flux of 35 mWb.