An iron rod and a zinc rod are respectively 25 . 55 cm and 25 . 5 cm at 0 ° C . At what temperature will they be exactly equal in length? α for iron = 0 . 00001 and α for zinc = 0 . 00003 ° C - 1 .

Length of iron initially l F e 0 = 25 . 55 cm Length of zinc initially l Z n 0 = 25 . 5 cm Now, l F e t = l Z n t l F e 0 1 + α F e t = l Z n 0 1 + α Z n t 25 . 55 1 + 10 × 10 - 6 t = 25 . 5 1 + 30 × 10 - 6 t 0 . 05 = 25 . 5 × 3 - 25 . 55 × 1 × 10 - 5 t t = 0 . 05 50 . 95 × 10 - 5 = 98 . 1 ° C

A hollow tube, made of steel, has length 5 m and internal cross-section 30 cm 2 . On passing steam through the tube, the temperature rises from 20 ° C to 100 ° C . What will be the increase in length and cross-section of the tube? Co-efficient of linear expansion of steel = 11 × 10 - 6 ° C - 1 .

For isotropic substance, α : β : γ = 1 : 2 : 3 ∴ γ = 22 × 10 - 6 ° C - 1 ∆ l = α × l ∘ × ∆ t ∆ l = 11 × 10 - 6 × 5 × 80 ∆ l = 0 . 44 cm ∆ A = α × A ∘ × ∆ t ∆ A = 22 × 10 - 6 × 30 × 80 ∆ A = 0 . 0528 cm 2

HARD

11th West Bengal Board

IMPORTANT

Earn 100

Define volume co-efficient and pressure co-efficient of expansion of gas. Show that in the case of a perfect gas, these two co-efficients of expansion are equal.

Important Questions on Thermal Expansion

HARD

11th West Bengal Board

IMPORTANT

A Text Book of PHYSICS PART I : CLASS 11>Chapter 16 - Thermal Expansion>EXERCISE>Q 16

From Boyle's and Charles' law deduce the equation of state of a perfect gas. What is universal gas constant? What is its value?

HARD

11th West Bengal Board

IMPORTANT

A Text Book of PHYSICS PART I : CLASS 11>Chapter 16 - Thermal Expansion>EXERCISE>Q 1

The temperature of a metal rod,

2.3 m

long is increased from

0 ° C

100 ° C

and the expansion in length of the rod was

2.75 mm

. Calculate the co-efficient of linear expansion of the metal.

HARD

11th West Bengal Board

IMPORTANT

A Text Book of PHYSICS PART I : CLASS 11>Chapter 16 - Thermal Expansion>EXERCISE>Q 2

An iron rod and a zinc rod are respectively

25.55 cm

and

25.5 cm

0 ° C

. At what temperature will they be exactly equal in length?

α

for iron

= 0.00001

and

α

for zinc

= 0.00003 ° C^{- 1}

HARD

11th West Bengal Board

IMPORTANT

A Text Book of PHYSICS PART I : CLASS 11>Chapter 16 - Thermal Expansion>EXERCISE>Q 3

A rectangular block of copper

(8 cm \times 5 cm \times 1 cm)

0 ° C

Is heated to

800 ° C

. Calculate the increase in volume. Co-

e f f^{n}

, of linear expansion of copper

= 0.16 \times 10^{- 4}

per

° C

HARD

11th West Bengal Board

IMPORTANT

A Text Book of PHYSICS PART I : CLASS 11>Chapter 16 - Thermal Expansion>EXERCISE>Q 4

A railway line is to be constructed by iron rails, each of which is

9 m

Long. If the temperature difference is

50 ° C

, what gap must be left between each two pieces?

α

for iron

= 1.2 \times 10^{- 5} ° C^{- 1}

HARD

11th West Bengal Board

IMPORTANT

A Text Book of PHYSICS PART I : CLASS 11>Chapter 16 - Thermal Expansion>EXERCISE>Q 5

The distance between Allahabad and Delhi is

600 km

. Find the total space that must be left between the rails to allow for a change of temperature from

36.5 ° F

in winter to

113 ° F

in summer. Co-efficient of linear expansion of iron

= 0.000012

per

° C

HARD

11th West Bengal Board

IMPORTANT

A Text Book of PHYSICS PART I : CLASS 11>Chapter 16 - Thermal Expansion>EXERCISE>Q 6

A hollow tube, made of steel, has length

5 m

and internal cross-section

30 {cm}^{2}

. On passing steam through the tube, the temperature rises from

20 ° C

100 ° C

. What will be the increase in length and cross-section of the tube? Co-efficient of linear expansion of steel

= 11 \times 10^{- 6} ° C^{- 1}

EASY

11th West Bengal Board

IMPORTANT

A Text Book of PHYSICS PART I : CLASS 11>Chapter 16 - Thermal Expansion>EXERCISE>Q 7

A scale made of steel, is correct at

15 ° C

. A certain distance measured with this scale at

30 ° C

, is found to be

600 m

. Find the error in measurement (

α

for steel

= 0.000011

per

° C

Define volume co-efficient and pressure co-efficient of expansion of gas. Show that in the case of a perfect gas, these two co-efficients of expansion are equal.

Important Questions on Thermal Expansion

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