Why the circuit Current (I) decrease, when Inductance (L) or inductive reactance (XL) increases in inductive circuit?

Explain the statement that " In Inductive circuit, when Inductance (L) or inductive reactance (X_L) increases, the circuit Current (I) decrease" 
OR
Why the circuit Current (I) decrease, when  Inductance (L) or inductive reactance (X_L) increases in inductive circuit?

Explanation:
We know that, I = V / R, 
but in inductive circuit, I = V/X_{L
So Current in inversely proportional  to the Current ( in inductive circuit.
Let's check with an example..}  
Suppose, when Inductance (L) = 0.02H 

V=220, R= 10 Ω, L=0.02 H, f=50Hz.

X_L = 2πfL = 2 x 3.1415 x 50 x 0.02 = 6.28 Ω 

Z = √ (R²+X_L²) = √ (10² + 6.28²) = 11.8 Ω

I = V/Z = 220/11.8 = 18.64 A

Now we increases Inductance (L) form 0.02 H to 0.04 H,

V=220, R= 10 Ω, L=0.04 H, f=50Hz.

X_L = 2πfL= 2 x 3.1415 x 50 x 0.04 = 12.56 Ω

Z = √ (R²+X_L²) = √ (10² + 12.56²) = 16.05 Ω

I = V/Z = 220 / 16.05 = 13.70 A

Conclusion:

We can see that, When inductance (L) was 0.02, then circuit current were 18.64 A,

But, when Circuit inductance increased from 0.02H to 0.04 H, then current decreased from13.70 A to 18.64A.

Hence proved,

In inductive circuit, when inductive reactance X_L increases, the circuit current decreases, and Vice Virsa.

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A (50/60 Hz) Transformer. Which one will give more Output? (When operates on 50 or 60 Hz frequency)

 A Transformer is designed to be operated on both 50 & 60 Hz frequency. 

For the Same rating, which one will give more out put; when,

1.  Operates on 50 Hz
2.   Operates on 60 Hz

Obviously! It will give more out put when we operate a transformer (of same rating) on 50 Hz instead of 60 Hz.

Because in previous posts, we proved that, in inductive circuit, when frequency increases, the circuit power factor decreases. Consequently, the transformer out put decreases.

Let’s consider the following example.

Suppose,

When Transformer operates on 50 Hz Frequency

Transformer = 100kVA, R=700Ω, L=1.2 H, f= 50 Hz.

X_L = 2πfL = 2 x 3.1415 x 50 x 1.2 = 377 Ω

Impedance Z = √ (R²+X_L²) = √ (700² + 377²) = 795 Ω

Power factor Cos θ = R/Z = 700/795 =0.88

Transformer Output (Real Power)

kVA x Cos θ

100kVA x 0.88

88000 W = 88kW

Now,

When Transformer operates on 60 Hz Frequency

Transformer =100kVA, R=700Ω, L=1.2 H, f= 60 Hz.

X_L = 2πfL = 2 x 3.1415 x 60 x1.2 = 452.4 Ω

Impedance Z = √ (R²+X_L²) = √ (700² + 452.4 ²) = 833.5 Ω

Power factor = Cos θ = R/Z = 700/833.5 =0.839

Transformer Output (Real Power)

kVA x Cos θ

100kVA x 0.839

=83900W = 83.9kW Output

Now see the difference (real power i.e., in Watts)

88kW- 83.9kW = 4100 W = 4.1kW

If we do the same (As above) for the power transformer i.e, for 500kVA Transformer, the result may be huge, as below.

(Suppose everything is same, without frequency)

Power Transformer Output (When operates on 50 Hz)

500kVA x 0.88 = 44000 = 440kW

Power Transformer Output (When operates on 60 Hz)

500kVA x 0.839 = 419500 = 419.5kW

Difference in Real power i.e. in Watts

440kW – 419.5kW = 20500 = 20kVA

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Why Power in pure Capacitive Circuit is Zero (0)?

We know that in Pure capacitive circuit, current is leading by 90 degree from voltage ( in other words, Voltage is lagging 90 Degree from current) i.e the phase difference between current and voltage is 90 degree.
So  If Current and Voltage are 90 Degree Out of Phase, Then The Power (P) will be zero. The reason is that,
We know that Power in AC Circuit
P= V I Cos φ
if angle between current and Voltage are 90 ( φ = 90) Degree. then
Power P = V I Cos ( 90) = 0
[ Note that Cos (90) = 0]
So if you put Cos 90 = 0→Then Power will be Zero (In pure capacitive circuit)

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Why Power in pure Inductive Circuit is Zero (0).

We know that in Pure inductive circuit, current is lagging by 90 degree from voltage ( in other words, Voltage is leading 90 Degree from current) i.e the pahse difference between current and voltage is 90 degree. 
So  If Current and Voltage are 90 Degree Out of Phase, Then The Power (P) will be zero. The reason is that,
We know that Power in AC Circuit
P= V I Cos φ
if angle between current and Voltage are 90 ( φ = 90) Degree. then
Power P = V I Cos ( 90) = 0
[ Note that Cos (90) = 0]
So if you put Cos 90 = 0→Then Power will be Zero (In pure Inductive circuit)

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Why Power in a circuit is Zero (0), in which Current and Voltage are 90 Degree out of phase?

If Current and Voltage are 90 Degree Out of Phase, Then The Power (P) will be zero. The reason is that, 
We know that Power in AC Circuit 
P= V I Cos φ
if angle between current and Voltage are 90 ( φ = 90) Degree. then
Power P = V I Cos ( 90) = 0
[ Note that Cos (90) = 0] 
So if you put Cos 90 = 0→Then Power will be Zero (In pure Inductive circuit)

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A Voltmeter, an ammeter (Ampere meter) and a battery cell are connected in series. It is observed that ammeter practically shows No Deflection. Why?

Due to the large resistance of the voltmeter, the circuit resistance becomes very high. As a result, very small current will flow in the circuit. this small current f on passing through the coil of voltmeter will produce some deflection. However, in case of ammeter (Ampere meter), most of this small current will flow through the shunt. Consequently the deflection of the ammeter will be practically nil.

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The Main difference between Active and passive Commonest (Very Easy Explanation with Examples)

Active Components:
Those devices or components which required external source to their operation is called Active Components. 
For Example: Diode, Transistors, SCR etc...
Explanation and Example: As we know that Diode is an Active Components. So it is required an External Source to its operation. 
Because,  If we connect a Diode in a Circuit and then connect this circuit to the Supply voltage., then Diode will not conduct the current Until the supply voltage reach to 0.3(In case of Germanium) or 0.7V(In case of Silicon). I think you got it :) 

Passive Components:
Those devices or components which do not required external source to their operation is called Passive Components. 
For Example: Resistor, Capacitor, Inductor etc...
Explanation and Example: Passive Components do not require external source to their operation. 
Like a Diode, Resistor does not require 0.3 0r 0.7 V. I.e., when we connect a resistor to the supply voltage, it starts work automatically without using a specific voltage. If you understood the above statement about active Components, then you will easily get this example. :)

In other words:
Active Components:
Those devices or components which produce energy in the form of Voltage or Current are called as Active Components
For Example: Diodes Transistors SCR etc…
Passive Components:
Those devices or components which store or maintain Energy in the form of Voltage or Current are known as Passive Components
For Example:  Resistor, Capacitor, Inductor etc...
In very Simple words;
Active Components: Energy Donor
Passive Components: Energy Acceptor
Also Passive Components are in linear and Active Components are in non linear category.

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