Which of the following principle is used to produce ''low-temperatures' ?
A. Super conductivity
B. Joule-Kelvin effect
C. Thermo-electric effect
D. Adiabatic demagnetisation
Answer: Option D
Solution (By Examveda Team)
Magnetic refrigeration is a cooling technology based on the magneto-caloric effect. This technique can be used to attain extremely low temperatures, as well as the ranges used in common refrigerators, depending on the design of the system. The magnetocaloric effect (MCE, from magnet and calorie) is a magneto-thermodynamic phenomenon in which a change in temperature of a suitable material is caused by exposing the material to a changing magnetic field. This is also known by low temperature physicists as adiabatic demagnetization, due to the application of the process specifically to create a temperature dropThis Question Belongs to General Knowledge >> Physics
Which of the following terms is not used in the field of physics?
A. Latent heat
B. Nuclear fusion
C. Refractive index
D. Stock value
Radiocarbon is produced in the atmosphere as a result of
A. Collision between fast neutrons and nitrogen nuclei present in the atmosphere.
B. Action of ultraviolet light from the sun on atmospheric oxygen.
C. Action of solar radiations particularly cosmic rays on carbon dioxide present in the atmosphere.
D. Lightning discharge in atmosphere.
It is easier to roll a stone up a sloping road than to lift it vertical upwards because
A. Work done in rolling is more than in lifting.
B. Work done in lifting the stone is equal to rolling it.
C. Work done in both is same but the rate of doing work is less in rolling.
D. Work done in rolling a stone is less than in lifting it.
The absorption of ink by blotting paper involves:
A. Viscosity of ink
B. Capillary action phenomenon
C. Diffusion of ink through the blotting
D. Siphon action
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