And you have done what so far?

 

im done with this question but i dont know the answer . this situation make me feel to know how to solve in correct ways .. im a beginner in this course... sorry for my bad english

 

Don't worry, your English is better than my (whatever native language you speak).

But, you won't get much of a response by just posting a bunch of problems. First, you should post one problem per post, otherwise it just gets too confusing. Second, you always need to show YOUR efforts to work YOUR problems. If you have specific questions about the problem, by all means ask; but don't expect someone to just work the solutions and provide them to you. Our goal is to help you identify where you went wrong and to guide you in a way so that you find your way back to the right path -- but in order to learn, you need to be the one that does the bulk of the struggling.

 

for question 1...
(a) superposition

when i open only one source that is current source ( 10mA) and voltage source will be short circuit. im confusing whether current can flow at 4k ohm ... can u explain more detail about it. tq

 

for question 1...
(a) superposition

when i open only one source that is current source ( 10mA) and voltage source will be short circuit. im confusing whether current can flow at 4k ohm ... can u explain more detail about it. tq

In order for current to flow in a resistor, you have to have a voltage across it. But if you short circuit a voltage source that is in parallel with it, then there is no way for a voltage to develop across the resistor. The key is to understand that replacing a voltage source with a short circuit, and a current source with an open circuit, is just a convenient way of setting the output of each type of source to zero in order to turn it "off". So a voltage source set to 0V output will produce or accept whatever current is required in order to maintain 0V across it.