Physics questions
20027 published questions with worked solutions.
- The wavelength of thermal radiation is:
- The frequency of thermal radiation is :
- Velocity of heat radiation is V and velocity of light is C they are related by :
- The wavelength _m corresponding to the maximum intensity:
- An ideal black body at room temperature is thrown in to a furnace it is observed that:
- A thin circular plate, a sphere and a cube of same mass and material are heated to 100°C temperature. Now if they are allowed to...
- The maximum wavelength of radiation emitted at 2000°k is 4 . What will be the maximum wavelength of radiation emitted at 2400°k?
- The maximum energy in the thermal radiation from hot source occur at a wavelength of 11 10^ -5 cm. According to Wiens law, the...
- A black body emites radiations of maximum intensity at a wavelength of 5000 A, when the temperature of the body is 1227°C. If the...
- The temperature of sun is 5500 K and it emitts maximum intensity radiation in the yellow region ( _m = 5.5 10^ -7 m). The maximum...
- At the temperature of the sun (6000k), the wavelength corresponding to the maximum radiation is about 550 nm. What will be the...
- The black body have
- A piece of charcoal and a piece of shining steel of the same area are kept for a long time in an open lawn in bright sun
- On investigation of light from three different stars A, B and C it was found that in the spectrum of A, the intensity of red...
- Three identical spheres of different materials iron gold and silver are at the same temperature. The one that radiates more...
- A polished metal plate with a rough black spot on it, is heated to about 1500 K and quickly taken to a dark room. The spot will...
- If a body is good absorber of heat then it is
- The essence of Kirchhoff's law is that a good absorber must be a
- Relation between emissivity e and absorptive power a is (for black body)
- Half part of ice block is covered with black cloth and rest half is covered with white cloth and then it is kept in sunlight....