A. transmits all incident radiations
B. absorbs all incident radiations
C. reflects all incident radiations
D. absorbs, reflects and transmits all incident radiations
Related Mcqs:
- Radiations from a black body are proportional to____________?
A. T1
B. T2
C. T3
D. T* - When a body reflects entire radiation incident on it, then it is known as____________?
A. white body
B. grey body
C. black body
D. transparent body - For the transmission of heat from one body to another__________?
A. temperature of the two bodies must be different
B. both bodies must be solids
C. both bodies must be in contact
D. at least one of the bodies must have some source of heating - Which of the following methods of heating is not dependent on the frequency of supply ?
A. Induction heating
B. Dielectric heating
C. Electric resistance heating
D. All of the above - In induction heating ___________ is abnormally high?
A. phase angle
B. frequency
C. current
D. voltage - For heating element high resistivity material is chosen to______________?
A. reduce the length of heating element
B. increase the life of the heating element
C. reduce the effect of oxidation
D. produce large amount of heat - In resistance heating highest working temperature is obtained from heating elements made of_____________?
A. nickel copper
B. nichrome
C. silicon carbide
D. silver - In an electric press mica is used_____________?
A. as an insulator
B. as a device for power factor improvement
C. for dielectric heating
D. for induction heating - In direct arc furnace, which of the following has high value ?
A. Current
B. Voltage
C. Power factor
D. All of the above - Resistance variation method of temperature control is done by connecting resistance elements in_____________?
A. series
B. parallel
C. series-parallel connections
D. star-delta connections
E. all of the above ways
