Question

Two identical resistors eac of resistance 10 o is connected in series ad parallel

Answer 1

Let r1=10Ω and r2=10Ω
Let R be the equivalent resistance.
1. Resistors connected in series
R=r1+r2=10+10=20Ω
2.Resistors connected in parallel
R=(1/r1)+(1/r2)=(r1*r2)/r1+r2=100/20=5Ω

Answer 2

1. resistirs connected in series....
r= r1+r2... so r= 10+ 10= 20 ohms

2. resistors conneted in parallel...
1/r=1/ r1+1/r2
1/r= 1/10+1 /10
.. =>1\20
so r= 20 ( by reciprocal)

hope it helps
@sonu