मराठी

Explain Why A Body with Large Reflectivity is a Poor Emitter - Physics

Advertisements
Advertisements

प्रश्न

Explain why a body with large reflectivity is a poor emitter

उत्तर १

According to Kirchh off’s law of black body radiations, good emitters are good absorbers and bad emitters are bad absorbers. A body with large reflectivity is a poor absorber of heat and consequently, it is also a poor emitter.

shaalaa.com

उत्तर २

A body with a large reflectivity is a poor absorber of light radiations. A poor absorber will in turn be a poor emitter of radiations. Hence, a body with a large reflectivity is a poor emitter.

shaalaa.com
Change of State - Latent Heat Capacity
  या प्रश्नात किंवा उत्तरात काही त्रुटी आहे का?
पाठ 11: Thermal Properties of Matter - Exercises [पृष्ठ २९७]

APPEARS IN

एनसीईआरटी Physics [English] Class 11
पाठ 11 Thermal Properties of Matter
Exercises | Q 21.1 | पृष्ठ २९७

संबंधित प्रश्‍न

Answer the following questions based on the P–T phase diagram of CO2:

CO2 at 1 atm pressure and temperature – 60 °C is compressed isothermally. Does it go through a liquid phase?


Answer the following questions based on the P–T phase diagram of CO2:

What happens when CO2 at 4 atm pressure is cooled from room temperature at constant pressure?


Answer the following questions based on the P–T phase diagram of CO2:

Describe qualitatively the changes in a given mass of solid CO2 at 10 atm pressure and temperature –65 °C as it is heated up to room temperature at constant pressure.


Answer the following questions based on the P–T phase diagram of CO2:

CO2 is heated to a temperature 70 °C and compressed isothermally. What changes in its properties do you expect to observe?


A ‘thermacole’ icebox is a cheap and efficient method for storing small quantities of cooked food in summer in particular. A cubical icebox of side 30 cm has a thickness of 5.0 cm. If 4.0 kg of ice is put in the box, estimate the amount of ice remaining after 6 h. The outside temperature is 45 °C, and coefficient of thermal conductivity of thermacole is 0.01 J s–1 m–1 K–1. [Heat of fusion of water = 335 × 103 J kg–1]


A brass boiler has a base area of 0.15 m2 and thickness 1.0 cm. It boils water at the rate of 6.0 kg/min when placed on a gas stove. Estimate the temperature of the part of the flame in contact with the boiler. The thermal conductivity of brass = 109 J s –1 m–1 K–1; Heat of vaporisation of water = 2256 × 103 J kg–1.


Answer the following question based on the P-T phase diagram of carbon dioxide:

What is the effect of decrease of pressure on the fusion and boiling point of CO2?


Answer the following question based on the P-T phase diagram of carbon dioxide:

What are the critical temperature and pressure for CO2? What is their significance?


During summers in India, one of the common practice to keep cool is to make ice balls of crushed ice, dip it in flavoured sugar syrup and sip it. For this a stick is inserted into crushed ice and is squeezed in the palm to make it into the ball. Equivalently in winter, in those areas where it snows, people make snow balls and throw around. Explain the formation of ball out of crushed ice or snow in the light of P–T diagram of water.


100 g of water is supercooled to –10°C. At this point, due to some disturbance mechanised or otherwise some of it suddenly freezes to ice. What will be the temperature of the resultant mixture and how much mass would freeze?

`[S_w = 1cal/g/^circC and L_(Fusion)^w = 80cal/g]`


Share
Notifications

Englishहिंदीमराठी


      Forgot password?
Use app×