1.   1 and 3  

3.  2 and 3

4.  1, 2 and 3

1.  RA and RB both have negative temperature coefficient

2.  RA and RB both have positive temperature coefficient

4.  RA has positive temperature coefficient and RB has negative temperature coefficient

2.  

3.  

4.  

1.  

3.  

4.  

1.  voltage series feedback

3.  current series feedback

4.  current shunt feedback

1.  a resistance in series with an ideal current source

3.  a resistance in parallel with an ideal voltage source

4.   none of these

1.  are parallel to one another

2.  intersect at 450

3.  intersect at 300

1.   1  

2.   2

3.  3

2.  

3.  

4.  

1.  same as that due to a d. c. source at equivalent magnitude

2.  half of that due to a d. c.

4.  none of these