Advertisements
Advertisements
प्रश्न
State two characteristics of a good thermion emitter.
State the characteristics required of good thermion emitter
उत्तर
Characteristics of a good thermion emitter:
1) The work function of the substance should be low so that electrons may be emitted from it even when it is not heated to a high temperature.
2) The melting point of the substance should be high so that it may not melt when it is heated to the temperature required for thermionic emission.
संबंधित प्रश्न
What is the energy absorbed during the phase change called?
Write the approximate value of specific latent heat of ice.
Answer the following:
Explain the role of latent heat in the change of state of a substance.
A thermally insulated pot has 150 g ice at temperature 0°C. How much steam of 100°C has to be mixed to it, so that water of temperature 50°C will be obtained? (Given : latent heat of melting of ice = 80 cal/g, latent heat of vaporization of water = 540 cal/g, specific heat of water = 1 cal/g °C)
Define the term ‘specific latent heat of fusion’ of a substance.
Explain the statement; “The specific latent heat of vaporization of wafer is 2260 × 103 J/kg”.
Explain, why no tracks are left on the ice during ice skating?
What observation you will record and how will you determine the specific latent heat of fusion of ice?
1 kg of water is contained in a 1.25 kW kettle. Assuming specific heat capacity of water = 4.2 J/g °C and specific latent heat of vaporization = 2260 J/g, calculate:
(i) the time taken for the temperature of water to rise from 25°C to its boiling point,
(ii) the mass of water which evaporates per minute from the boiling water.
Specific latent heat of vaporisation : J/kg : : specific heat : _______
Find the odd one out and give its explanation.
Define boiling point of a liquid.
The latent heat of vaporisation is a term referred for the conversion of gas into liquid.
During reheating, ice is converted to water at a temperature of 0 °C.
Write scientific reason.
Even if boiling water is constantly heated, its temperature does not rise.
Define specific latent heat capacity
Who introduced the term latent heat?
Calculate the amount of heat required to convert 200g of ice at 0°C into the water at 0°C Specific latent heat of fusion of ice = 336 Jg-1
