Electric circuit

Electric circuit

 An electrical Circuit is a Complete path or lines for the flow of an electrical Current which Consists of Source of Supply Connecting wires, Switches and load .

now a day we use more number electric gadgets. All these devices should have complete electrical current path. Such a complete electric path is called as a circuit. A circuit should have a source of supply, load, insulated conductor to carry the current and a switch to control the circuit.

When the current starts from the +ve terminal of the cell and passes through the load and returns back to the same place by passing the -ve terminal is known as the electric circuit or it can be defined as the path around which the electric current moves. 

An electric circuit consists Voltage source , connecting wire , load and switch .

Types of Electric circuit : 

There are three types of Electric circuit .

1) open circuit

2) closed circuit

3) short circuit

1) open circuit : 

open circuit is not a complete circuit for flow of Electric current is sold to be open circuit.

It is that circuit in which the +ve or -ve wire or the load wire is broken, as a result the current will not flow through the load.

 a battery is on an open circuit when it is not supplying current to the circuit, that is the switch is open,  A wall socket, too, is an open circuit if no appliance is connected to it. Although there is no current flow, if there is no switch, there will be a voltage across the socket which will be live .

2) closed circuit :

Closed circuit

 the circuit in load start working when there is flow of current and that's called closed circuit.  closed circuit is a complete Electric circuit through which Electric current is flow when current is applied and the complete pathway of the current flow from the battery by the switch and load back to the battery.

3) short circuit :

 an axidently +ve and -ve terminal touch each other in working condition that's called short circuit .in this case fuse get blown out and automatically switch off the current .

Some most important question and answer for technical exam : 

1. Two coupled coils with L = L₂ =0.6 Have a coupling coefficient of K=0.8. the turns ratio N1 /N2is

a. 4 

b. 2

c. 1

 

d. 0.5                                            Ans=C

2. The value of V in the circuit shown in given figure is 

a. 1 V

b. 2 V

c. 3 V

d. 4 V                                             Ans=C

3. In the figure shown below, if we connect a source of 2V, with internal resistance of 1Ωat AA' with positive terminal at A, then current through R is

a. 2 A

b. 1.66 A

c. 1A

d. 0.625 A                                     Ans=D

4. Two heaters rated at 1000w, 250V each are connected in series across a 250V, 50Hz AC mains. The total power drawn from the supply would be

a. 1000W

b. 500W

c. 250W

d. 2000W                                       Ans=B

5. The efficiency for maximum power transfer to the load is

a. 25%

b. 50%

c. 75%

d. 100%                                          Ans=B

6.  The value of current I flowing in the 10 resistor in the circuit shown in the figure below will be

a. 10A

b. 6A

C. 5A 

d. OA                                              Ans= C

7. The curve representing Ohm's law is

a. Linear

b. Hyperbolic

c. Parabolic

d. Triangular                                 Ans=A

8. The time constant of the network shown in figure is 

a. 2RC

b. 3RC

c. RC/2

d. 2RC/3                                         Ans=D

9. A voltage divider circuit and its Thevenin's equivalent are shown below. The value of Vth and Rth will be

a. 10 V, 80Ω

b. 4 V, 80 Ω

c. 4 V, 48 Ω

d. 5 V, 50 Ω                                   Ans=C

10. The V-I relation for the network shown in the given box is V= 41-9. if now a resistor R=20 is connected across it, then the value of I will be

a. -4.5A 

b. -1.5A

c. 1.5A

d. 4.5A                                               Ans=D

11. Three resistance of 50 each are connected in star, values of equivalent delta resistances are

a. 1.50Ω each

b. 2.50 Ω each

c. 5/30 Ω each

 d. 15 Ω each                               Ans=D

12. A voltage source having an open-circuit voltage of 150V and internal resistance of 75Ω is equivalent to a current source of

a. 2 A in series with 75Ω

 b. 2 A in series with 37.5Ω

c. 2 A in parallel with 75Ω

 d. 1 A in parallel with 150Ω.       Ans=C

13.super theorem require as many circuit to be solved as there are

a. nodes

b. Sources

c. Loops

d. None of these                           Ans=B

14. A complete Electric circuit is called.......

A. Open circuit

B. Closed circuit

C. Complete                             Ans=c

15 . A device that used to break the circuit is called......

A. Cell

B. Switch

C. Wire

D. None of the above.                 ANS=B

16.How many types of electric circuits are there ?

A.open

B. Closed

c.short

D. All of the above.                      ANS=D