Question

Chapter 12, Problem os Dermatologists often remove small precancerous skin lesions by freezing them quickly with liquid nitrogen, which may have a temperature as low as 10.9 K. What is this temperature on the (a) Celsius and (b) Fahrenheit scales? - (a) Number Units (b) Number 17 Units Click if you would like to show Work for this question: Doen Show Work

Answer 1

5.

a. The temperature of liquid nitrogen is 80.9 K.

So, the temperature of liquid nitrogen in degree Celsius is

80.9 -273.15 = -192.25°C.

And the temperature of liquid nitrogen in Fahrenheit is

9 -- 192.25 x +32 = -314.05° F

10.

Linear thermal expansion coefficient for steel is 13 X 10-⁶  /°C.

So, the contraction in length of steel pipes due to the change in temperature from 18.7°C to -44.7°C is

L = Lo(1 + QAT

or, $\small L -L_{0}= L_{0} \alpha \Delta T$

or, $\small \Delta L= 63.3 \times 13 \times 10^{-6} \times (-44.7-18.7) = 0.052 2 \,\, m$

Hence, the change in length of pipe is 5.22 cm.

12.

We have

$\small \Delta L= L_{0} \alpha \Delta T$

Given, change in length = 19.4 cm = 0.194 m

Change in temperature = 41 - (-9) = 50°C

Putting all the given values in the equation, we get

$\small 0.194 = L_{0} \times 13 \times 10^{-6} \times 50$

or, $\small L_{0} = 298.46 \,\, m$

Hence, the approximate height of the Eiffel tower at lower temperature is 298.5 m.