A student records the initial length L , change in temperature Δ T and change in length Δ L of a rod as follows: S.NO L m Δ t C 0 Δ L ( m ) 1 2 10 4 × 10 - 4 2 1 10 4 × 10 - 4 3 2 10 2 × 10 - 4 4 3 10 6 × 10 - 4 If the first observation is correct, what can you say about observations 2 , 3 and 4 .

The coefficient of linear expansion is characteristic of the material of the rod. Hence, it will remain the same in all the four observations. From the I st observation: α = Δ L L Δ t = 4 × 10 - 4 2 × 10 = 2 × 10 - 5 ° C - 1 From the second observation, the change in length: Δ L = α L Δ t = 2 × 10 - 5 × 1 × 10 = 2 × 10 - 4 m ≠ 4 × 10 - 4 m Hence, the observation 2 is incorrect. For the third observation: Δ L = α L Δ t Δ L = 2 × 10 - 5 × 2 × 20 = 8 × 10 - 4 m = 2 × 10 - 4 m Hence, the observation 3 is incorrect. For the fourth observation: Δ L = α · L Δ t Δ L = 2 × 10 - 5 × 3 × 10 = 6 × 10 - 4 = 6 × 10 - 4 m Hence, observation 4 is correct.

E M B I B E

NCERT Exemplar Physics - Class 11>Chapter 11 - Thermal Properties of Matter>VSA

NCERT Solutions for Chapter: Thermal Properties of Matter, Exercise 3: VSA

Author:NCERT

NCERT Physics Solutions for Exercise - NCERT Solutions for Chapter: Thermal Properties of Matter, Exercise 3: VSA

Attempt the practice questions on Chapter 11: Thermal Properties of Matter, Exercise 3: VSA with hints and solutions to strengthen your understanding. NCERT Exemplar Physics - Class 11 solutions are prepared by Experienced Embibe Experts.

Questions from NCERT Solutions for Chapter: Thermal Properties of Matter, Exercise 3: VSA with Hints & Solutions

EASY

11th CBSE

IMPORTANT

NCERT Exemplar Physics - Class 11>Chapter 11 - Thermal Properties of Matter>VSA>Q 11.13

Is the bulb of a thermometer made of diathermic walls or adiabatic walls?

MEDIUM

11th CBSE

IMPORTANT

NCERT Exemplar Physics - Class 11>Chapter 11 - Thermal Properties of Matter>VSA>Q 11.14

A student records the initial length $L$ , change in temperature $Δ T$ and change in length $Δ L$ of a rod as follows:

S.NO	$L (m)$	$Δ t ({}^{0}C)$	$Δ L (m)$
1	$2$	$10$	$4 \times 10^{- 4}$
2	$1$	$10$	$4 \times 10^{- 4}$
3	$2$	$10$	$2 \times 10^{- 4}$
4	$3$	$10$	$6 \times 10^{- 4}$

If the first observation is correct, what can you say about observations $2, 3$ and $4$ .

MEDIUM

11th CBSE

IMPORTANT

NCERT Exemplar Physics - Class 11>Chapter 11 - Thermal Properties of Matter>VSA>Q 11.15

Why does a metal bar appear hotter than a wooden bar at the same temperature? Equivalently it also appears cooler than wooden bar if they are both colder than room temperature.

MEDIUM

11th CBSE

IMPORTANT

NCERT Exemplar Physics - Class 11>Chapter 11 - Thermal Properties of Matter>VSA>Q 11.16

Calculate the temperature which has same numeral value on celsius and Fahrenheit scale.

MEDIUM

11th CBSE

IMPORTANT

NCERT Exemplar Physics - Class 11>Chapter 11 - Thermal Properties of Matter>VSA>Q 11.17

These days people use steel utensils with copper bottom. This is supposed to be good for uniform heating of food. Explain this effect using the fact that copper is the better conductor.

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