basic que on thermal

two spheres of same size are made of the same material but one is solid and the other is hollow. They r heated to same temp.Which will expand more, if not why?

16 Answers

1
Aditya ·

They will expand to the same extent according to the formula,

V-V0=V0γΔT....as γ is same for both.

1
prateek punj ·

yups i too think so....

But also hav a doubt inside there is air which will also expand accordingly .....so volumetric expansion toh air ki count hogi na.....

1
ANKIT GOYAL ·

there u r rite volumetric expansion of the air will be considered
so hollow will be more expanded

1
prateek punj ·

here i hav edited please check....

1
ANKIT GOYAL ·

i toooooo

1
Aditya ·

What if there is vacuum inside?

1
ANKIT GOYAL ·

ur ans would be rite

1
prateek punj ·

nothing is mentioned so......wat to do.....

1
prateek punj ·

arey yaar aise to kahin bhi kuch bhi assume karke ans aa jayega....

1
Aditya ·

lol...;)[6]

1
ANKIT GOYAL ·

specify nahin kiya hai

11
rkrish ·

Expansion of similar solid & hollow spheres heated to same temp.

Thermal expansion of a cavity (irrespective of air,or vacuum) is same as if it had been a solid of same dimensions made of the same material.
So think of the hollow sphere to be a solid sphere with a cavity of almost same radius.

So,
Expansion of solid sphere = V γ Δθ
Exansion of hollow sphere(ie. considering solid sphere + cavity) = V γ Δθ

Since V,γ,Δθ are same for both , Expansion will be same for both solid & hollow spheres.

11
rkrish ·

Expansion of similar solid & hollow spheres supplied same amount of heat

Δθ = Q/mc

Since Q and c are same , Expansion of hollow sphere will be more than solid sphere bec. hollow sphere has lesser mass than solid sphere of same volume.

1
Mani ·

For the hollow sphere we must take in account of only the expansion of surface area and not the voulme
which is 2/3 of gamma
when we proceed further the expansion of volume in hollow will be greater

11
virang1 Jhaveri ·

@rkrish
Q supplied is not the same but the temperature is same

1
Aditya ·

Virang..
see the 13th post..!

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