DC Pandey Solutions: Thermometry, Thermal Expansion & Kinetic Theory of Gases - 1

# DC Pandey Solutions: Thermometry, Thermal Expansion & Kinetic Theory of Gases - 1 | Physics Class 11 - NEET PDF Download

Introductory Exercise 17.1

Ques 1: What is the value of
(a) 0°F in celsius scale?
(b) 0 K on Fahrenheit scale?
Sol:

Putting TF = 0, we get TC = - 17.8°C

Ques 2: At what temperature is the Fahrenheit scale reading equal to (a) twice (b) half of Celsius?
Sol:

Putting TF = 2Twe get TC = 160° C

Ques 3: A Fault y thermometer reads 5°C in melting ice and 99°C in steam. Find the correct temperature in °F when this faulty thermometer reads 52°C.
Sol:

∴ TC = 50°c

Now using the equation,
Putting TC = 50° C, we get TF = 122°F

Ques 4: At what temperature the Fahrenheit and Kelvin scales of temperature give the same reading?
Sol:

Putting TF = TK,
We get, TF or TK = 574.25

Ques 5: At what temperature the Fahrenheit and Celsius scales of temperature give the same reading?
Sol:

Putting TC =TF, we get
TC or TF =-40°C or -40°F

Ques 6: A pendulum clock of time period 2 sec gives the correct time at 30°C. The pendulum is made of iron. How many seconds will it lose or gain per day when the temperature falls to 0°C?
αFe = 1.2 × 10-5 (°C)-1.
Sol:

Temperature is decreased. Hence l or T will decrease. So it will gain time.

= 15.55 s

Ques 7: A block of wood is floating in water at 0°C. The temperature of water is slowly raised from 0°C to 10°C. How will the percentage of volume of block above water level change with rise in temperature?
Sol:
Density of water will increase by increasing the temperature from 0 to 4°C, then it will decrease. Fraction of volume immersed is given by

ρ1 is first increased the decreased first decreased the increased.
Or percentage of volume above water level will first increased then decreased.

Ques 8: A piece of metal floats on mercury. The coefficient of volume expansion of metal and mercury are γ1 and γ2 respectively. If the temperature of both mercury and metal are increased by an amount ΔT, by what factor does the fraction of the volume of the metal submerged in mercury changes?
Sol:

Neglecting γ1γ2(DT)2 term, we get

Ques 9: A brass disc fit s snugly in a hole in a steel plate. Should you heat or cool the system to loosen the disc from the hole? Given that αB > aFe.
Sol:

Since, αB >αFe
On cooling brass will contract more.

Ques 10:Show that the volume thermal expansion coefficient for an ideal gas at constant pressure is 1/T.
Sol:
PV = nRT ...(i)
At constant pressure we can write the above equation as
PdV = nRdT .
∴   ...(ii)

Substituting in Eq. (ii),

or  ...(iii)
Now we have an equation,

From Eqs. (iii) and (iv), we get, γ= 1/T

The document DC Pandey Solutions: Thermometry, Thermal Expansion & Kinetic Theory of Gases - 1 | Physics Class 11 - NEET is a part of the NEET Course Physics Class 11.
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## Physics Class 11

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## FAQs on DC Pandey Solutions: Thermometry, Thermal Expansion & Kinetic Theory of Gases - 1 - Physics Class 11 - NEET

 1. What is thermometry and why is it important in the study of temperature?
Ans. Thermometry is the scientific measurement of temperature. It is important in the study of temperature as it helps us understand the behavior of matter at different temperature levels, allows us to accurately measure and control temperature in various applications, and provides valuable data for studying thermal properties of substances.
 2. How does thermal expansion occur in different materials?
Ans. Thermal expansion occurs in different materials due to the increase in their atomic or molecular vibrations with an increase in temperature. This causes the atoms or molecules to move apart, resulting in an overall expansion of the material. The extent of expansion depends on the material's coefficient of linear or volumetric expansion, which varies for different substances.
 3. What is the kinetic theory of gases and what does it explain?
Ans. The kinetic theory of gases is a scientific model that explains the behavior of gases based on the motion of their particles. It states that gas particles are in constant random motion and have negligible volume compared to the container they occupy. The theory explains concepts such as pressure, temperature, and volume of gases, and provides insights into gas laws and their applications.
 4. How can thermometers be calibrated to ensure accurate temperature measurements?
Ans. Thermometers can be calibrated by comparing their readings to a reference temperature scale. This can be done using known fixed points, such as the freezing and boiling points of water, and adjusting the thermometer's scale accordingly. Calibrating thermometers ensures accurate temperature measurements by aligning them with a standardized scale that is universally accepted.
 5. What are some practical applications of thermometry, thermal expansion, and the kinetic theory of gases?
Ans. Some practical applications include temperature measurement in weather forecasting, medical diagnosis, and industrial processes; designing and operating systems that account for thermal expansion to prevent damage or failure; and understanding and predicting gas behavior in engines, refrigeration systems, and chemical reactions. These concepts have wide-ranging applications in various fields.

## Physics Class 11

102 videos|411 docs|121 tests

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