Archana Shukla Solutions for Chapter: Heat and Temperature, Exercise 8: EVALUATE

How can heat loss through radiation be reduced in a vacuum flask? Explain with a diagram.

Hot water system and refrigerator also work on the same principle. How is their working similar? Explain.

Observe the given diagram of a thermometer. The distance between $-{10}^{\mathrm{o}} \mathrm{C}$ and the ${110}^{\mathrm{o}} \mathrm{C}$ markings is $25 \mathrm{cm}$. If the length of the mercury thread is $15 \mathrm{cm}$ as shown in the figure, calculate the temperature measured by this thermometer.

Rama was boiling water in a kettle. Her mother asked what is the temperature of boiling water? She replied that it is $239° \mathrm{F}$.

Calculate the temperature of boiling water in degrees Celsius.

Rama was boiling water in a kettle. Her mother asked what is the temperature of boiling water? She replied that it is $239 °\mathrm{F}$.

Did Rama answer correctly?

Amit had two balls $\text{'}\mathrm{P}\text{'} \mathrm{and} \text{'}\mathrm{Q}\text{'}$made of paraffin. The masses of balls $\text{'}\mathrm{P}\text{'} \mathrm{and} \text{'}\mathrm{Q}\text{'}$ are $1 \mathrm{kg} \mathrm{and} 2 \mathrm{kg}$, respectively. He immersed both the balls in a water bath containing hot water. He observed that ball $\text{'}\mathrm{P}\text{'}$ melts faster than ball $\text{'}\mathrm{Q}\text{'}$. Why is that so?

Akshat's mother had to set curd. She added a small amount of curd to warm milk. The microbes present in the curd help in setting if this mixture is kept approximately between $35° \mathrm{C} \mathrm{to} 40° \mathrm{C}$. In colder regions, generally, the setting of curd becomes difficult. Suggest a way to set curd in such a situation.

The lengths of mercury thread in a mercury thermometer are given here. Length in melting ice $=20 \mathrm{mm}$, length in steam above boiling water $=170 \mathrm{mm}$, length in liquid $\mathrm{P}=50 \mathrm{mm}$. What is the temperature of liquid $\mathrm{P}$?