Question

Two resistors of of resistances R1=100+-3 ohm , R2=200+-4 ohm are connected in i) series ii) Parallel. Use for (i) R=R1+R2 and for (ii) 1/R=1/R1 +1/R2 and ΔR/R2= ΔR1/R1^2+ ΔR2/R2^2 .

Answer 1

Answer:

R eq =R  1  +R 2 =300

△R  eq  =△R 1  +△R  2

​△R  eq  =3+4=7

Req=300±7ohm

b) Parallel

R  eq 1  = R  11 ​   +  R  2 1

​R eq 1 = 100  +  200  =R eq  = 3 200

​R eq △R  eq  =  R  1 △R  1  + R  2 △R 2

​⇒  200△R  =  100 +  200

△R=  3

6+4 =10

​ ⇒△R=  10

​R= 200  ±  10  Ohm