COMEDK Exam 2018 Solved Paper

Since, the terminals of battery is connected at one quarter distance. Hence, ratio of lengths between two parts will be
‌‌

l1

l2

=‌

1

3

‌⇒‌‌l1:l2=1:3
‌‌ Since, ‌R∝l
‌∴‌‌R1:R2=1:3
‌R1=‌

24

1+3

=6Ω
‌R2=24×‌

3

1+3

=18Ω
Since, potential difference across R1 and R2 is same, so they are connected in parallel.
∴ Equivalent resistance of R1 and R2,
R′‌=‌

R1R2

R1+R2

‌=‌

6×18

6+18

=4.5Ω
∴ Total resistance, RT=R′+r
=4.5+1.5‌‌[∵r=1.5Ω]
‌=6Ω
Current, I=‌

V

RT

=‌

18

6

=3A
According to current division rule, current through bigger are (i.e. through R2 )
IR2=I⋅‌

R1

R1+R2

=3×‌

6

6+18

=0.75A