Electronics - Parallel Circuits - Discussion

Total current in circuit is I= p/v; 9.408/48 = 0.196.

And sum of current through r2, r3 & r3 equals to 0.052.

Current through r1 is 0.048.

And sum of the current through r1, r2, r3, and r4 is 0.102.

The difference between this is 0.196 - 0.102 = 0.092.

They r1 has wrong value r1 t = should have value 144K ohm.

@Vignesh.

Its watt-meter not a voltmeter. It connects + and - terminal. So it will work.

One way to start is that, the power comes from the smallest resistor. So, after verifying that currents through R3 and R2(0.04A) and R4(0.012) sum up to 0.052A, we search for a smaller value for R1 that could elevate the power to 9.408W which is exactly 1/3K.

I=v/r so I=48/1*10^3
so i=0.48
but here ammeter shows the value of 0.053
so here we have to change the value of resistance.

I1=V/R=48/1K=48mA=0.048A
It=I1+0.052(in circuit itself)
It=0.048+0.052=0.1A
It=0.1A

P=VI
P=48*0.1=4.8W

so the watt meter reading should be 4.8 watts but the circuit shows 9.408W.

so mistake in R1.

Answer is A

@ vinoth: that's a wattmeter..not a voltmeter...

@ H@R you are correct!

Circuit itself wrong. voltmeter is connected in series with circuit no current flows.

P = V*I .... I = P/V = 9.408/48 = 0.196A (Total Current)
Current on R1 = 0.196 - 0.052 = 0.144A
R1 = 48V/0.144A = 333.33 Ohm (Should be the correct value of R1)

Given total power=9.408
Power of r1=48/1*1000=.48mW
r2=48/2*1000=.24mW
r3=48/3*1000=.16mW
r4=48/4*1000=.12mW

Total power = 1W
But the total power given=9.408W.
ie, one resistor is wrong value.
................................................................

0.012A is current through R4
I R4= 48/4*1000 = .012A

So R4 is correct value
.................................................................

0.053 is the current total through r2, r3 and r4 as branch current total.
.........................................................................

We know that current through R4=.012

I (R2+R3) = V/(R2*R3/R2+R3)

=48/(2*3/2+3)1000
=48/(6/5)1000
=48/1200
=.04

Then I(R2+R3+R4)= .04+.012 = .052

So that R2,R3,R4 are correct.

i.e. R1 is wrong