Which Of The Following Is The Example Of Diathermanous Substance?

Substances which allow transmission of infrared radiation through them are called athermanous substances. – For example, wood, metal, CO2​, water vapors, etc. Diathermanous substances – Substances that don’t allow transmission of infrared radiation through them are called diathermanous substances.

What is meant by Diathermanous?

Diathermancy (from “dia” through and “thermē” heat) is the property of some fluids that allows rays of light through them without itself being heated. A diathermanous substance is thus “permeable” by heat.).

What is the value of coefficient of transmission for Athermanous substance?

The substances which cannot transmit the radiant heat incident upon their surfaces are called adiathermanous (athermanous) substances. For such a substance, the value of the coefficient of transmission (t) is zero.

What is the value of coefficient of transmission?

Transmission coefficients can be calculated for either the amplitude or the intensity of the wave. Either is calculated by taking the ratio of the value after the surface or element to the value before.

Is an example of Diathermanous substance?

A body which allows heat radiation to pass through it is called a Diathermanous Body(diathermic or diathermal bodies). Example: oxygen, quartz, hydrogen, iodine.

What is meant by angle of contact?

physics. : the angle between the meniscus and the containing walls of a column of liquid measured from the vertical wall below the surface of the liquid to the position of the tangent to the meniscus at its point of contact with the wall.

What do you mean by absorption coefficient?

: the fraction of incident radiant energy which is absorbed per unit thickness, per unit mass, or per atom of an absorber. — called also coefficient of absorption.

What is an opaque body?

Opaque bodies are the materials which do not allow light to pass through the at all. They are not called opaque medium because the object have a microscopic shape and size. opaque object not called opaque medium because the object have a microscopic shape , size .

Is dry air is Diathermanous?

(13) Diathermanous Medium : A medium which allows heat radiations to pass through it without absorbing them is called diathermanous medium. … (i) Dry air does not get heated in summers by absorbing heat radiations from sun. It gets heated through convection by receiving heat from the surface of earth.

Which of the following substances is opaque to radiant energy?

Benzene – this is a hydrocarbon which is known to be very stable. It’s chemical formula is C6H6 . These compounds are both chemically and thermodynamically stable, hence very opaque to radiant heat or thermal radiation.

When a is absorptivity P is reflectivity and T is transmissivity then for a Diathermanous body?

Diathermancy is the property of some fluids that allows rays through them without itself being heated. So for diathermanous body reflectivity and absorbtivity will become zero.

How is the heat defined?

Heat is the form of energy that is transferred between systems or objects with different temperatures (flowing from the high-temperature system to the low-temperature system). Also referred to as heat energy or thermal energy. Heat is typically measured in Btu, calories or joules.

How do you use absorption coefficient?

You can calculate the absorption coefficient using this formula: α=2.303*A/d, where d is thickness, A is absorption and α is the absorption coefficient, respectively. @Md.

What is the absorption coefficient of water?

According to the estimations, the absorption coefficient is 0.135cm1 at 25 °C water temperature and decreasing with temperature rise at a rate of 5.7 × 104 cm1 C1. The measured decrease of the absorption coefficient was approximately 20%-22% in the temperature range 25 °C – 70 °C.

What is angle of contact give example?

Angle of contact is the angle at which a liquid interface meets a solid surface. It is denoted by θ. It is different at interfaces of different pairs of liquids and solids. For example: – Droplet of water on louts leaf. The droplet of water(Liquid) is in contact with the solid surface which is leaf.

What is the importance of angle of contact?

Importance of angle of contact

The contact angle determines whether a liquid will spread on the surface of a solid or form droplets on it. If the Angle of contact is obtuse: then a droplet will be formed.

What are the factors affecting the angle of contact?

Two factors affecting the angle of contact:

  • The nature of the liquid and the solid in contact.
  • Impurities present in the liquid change the angle of contact.

What is a perfect blackbody how can it be realized in practice?

(1) A perfectly black body is that which absorbs completely the radiations of all wavelengths incident on it. … (6) A perfectly black body can not be realised in practice but materials like Platinum black or Lamp black come close to being ideal black bodies. Such materials absorbs 96% to 85% of the incident radiations.

What is SI unit of emissive power?

SI unit : the watt per square metre (W/m2).

What is emissive power?

: the energy of thermal radiation emitted in all directions per unit time from each unit area of a surface at any given temperature.

How do you calculate intensity coefficient of transmission?

The intensity reflection coefficient for any boundary between two media is given by a=(Z2−Z1)2(Z1+Z2)2 a = ( Z 2 − Z 1 ) 2 ( Z 1 + Z 2 ) 2 , and the acoustic impedance of muscle is given in Table 1.