Discussion in 'General Electronics Chat' started by munna007, Jun 29, 2011.

1. ### munna007 Thread Starter Active Member

Jul 23, 2008
51
0
Hello friends....in this questions the answer is (b) option.....this is from indian engg. services exam.

if we apply mesh in loop which i have shown , then we find that

I = (10 - 5 )/10 = 0.5 amp

V=10 - 6 I = 7 volt (right acc. to answer keys)

and Rth = 2.4 ohm (i have calculated Rth)

but if we apply Nodal analysis where V is marked then

acc to that
(V-10)/6=(V-5)/4
V= -5

so we see that both results r not equal....but in answer keys 7 volt is given....
plz tell me what is the problem in second method of nodal analysis.? is this wrong ?

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2. ### The Electrician AAC Fanatic!

Oct 9, 2007
2,368
353
There are two currents entering the node marked V; their sum must be zero. You have set them equal rather than setting one equal to the negative of the other.

Let your equation be (V-10)/6 = -(V-5)/4 and you will get V = 7.

3. ### munna007 Thread Starter Active Member

Jul 23, 2008
51
0
thanku so much sir....i understood my mistake....