COMEDK Exam 2019 Solved Paper

Ratio of diameters, ‌

d1

d2

=‌

1

2

Ratio of lengths, ‌

l1

l2

=‌

2

1

The rate of heat conduction is given by the formula,
H=‌

dQ

dt

=k‌

A

l

∆T
where, dQ is the amount of heat transferred in dt time, k is coefficient of heat conduction for a particular material. Since, ∆T is same in both cases, the ratio is
‌

H1

H2

‌=‌

A1l2

A2l1

⇒‌‌‌

H1

H2

‌=‌

d12l2

d22l1

=‌

1

4

×‌

1

2

⇒R=1:8