Question

two rods of the same length and material transfer a given amount of heat in 12 s when they joined end to end . but when they are joined lengthwise they will transfer the same amount of heat in

Answer 1

Answer:

it can help you

follow me and make brilliant answer

Both rods of same length, material and axis sectional area so their thermal conductivities (k) would be $be same

also, thermal resistance

P

m

=

KA

L

⇒

R

2

R

1

=

K

1

K

2

[K→ conductivity in series / parallel]

also thermal transfer

Δt

ΔQ

=

R

ΔT

[ΔQ= Heat transformed $$\Delta T: Temperature difference]

That mass for same ΔQ & ΔT

Δ tαR t(2) [Δt= time taken]

From (1) & (2) gives

Δt

2

Δt

1

=

R

2

R

1

=

K

1

K

2

given Δt

1

=125

In parallel connection K

1

=2K But in series K

2

=K/2 so:-

Δt

2

Δt

1

=

2K

K/2

=

4

1

⇒Δt

2

=4Δt

1

=4×12=48