Electronics - Parallel Circuits - Discussion

1) 0=(I2-I1)X1K+(I2-I3)X2K
2) 0=(I3-I2)X2K+(I3-I4)X3K
3) 0=(I4-I3)X3K+I4X4K (R4=4k)

From given figure I1=I2=I3=I4=2.4A Substituing in 1,2,3

It satifies 1,2 it will be true and for 3 if R4 is shorted.

@Pankaj explained well..

Here asking for which resistor will work as open circuit and short circuit..

2.4A is going to next branch that means no current passing through R1, R2,R3 so it will work as open circuit.

R4 is only one through which current is passing ..so it behaves as short circuit.!! :)

@Meghavi.
If R4 is Shorted then there would be no resistor in the circuit. Then how will the current flow and moreover how will you apply Ohms law V=IR.

What is G here all value same 2.400G.

G stands for Galvanometer here i suppose, that's why 'A' is written by its side to show that it is being used an ammeter.
& since current is same in all branches therefore,r1,r2,r3 are open and only r4 is in circuit..

Here G stands for galvanometer itself. But 2.400G doesn't mean that the current in branch is 2.400GA. It just indicate the strength of galvanometer up to which it can measure the current. Since all the resistors are in parallel and the circuit acts as current divider more current flows from 1kohm and the rest is divide among others r4 gets less amount of current showing high resistance and low conductance. In general short circuit is nothing but the path for current having low impedance (high conductance) so the component which should be shorted should be r1.

Pankaj answer is the best explained. See the value all the galvanometer is same. It tells that current is not passing through R1, R2, R3. The entire current 2. 400A is passing through R4.

Last two Components are Shorted. Because of no junction point is there.

Because R4 is the final circuit which closes the loop.