If the radius of star is R and it acts as a black body, what would be the temperature
If the radius of star is R and it acts as a black body, what would be the temperature of the star, in which the rate of energy protection is Q?
Options
(a) Q […]
Questions
Water rises in a vertical capillary tube up to a height of 2.0 cm.
Water rises in a vertical capillary tube up to a height of 2.0 cm. If the tube is inclined at an angle of 60⁰ with the vertical, then up to what length the water will […]
The total radiant energy per unit area, normal to the direction of incidence
The total radiant energy per unit area, normal to the direction of incidence, received at a distance R from the centre of a star of radius r, whose outer surface radiates as a black body […]
Heat is flowing through a rod of length 50 cm and area of cross-section 5 cm².
Heat is flowing through a rod of length 50 cm and area of cross-section 5 cm². Its ends are respectively at 25⁰C and 125⁰C. The coefficient of thermal conductivity of the rod is 0.092 k.cal/m […]
A liquid wets a solid completely. The meniscus of the liquid in a sufficiently long
A liquid wets a solid completely. The meniscus of the liquid in a sufficiently long tube is
Options
(a) Flat (b) Concave (c) Convex (d) Cylindrical
Correct Answer:
Concave
Explanation:
Meniscus of liquid which […]
A black body at 227⁰C radiates heat at the rate of 7cals/cm²s. At a temperature
A black body at 227⁰C radiates heat at the rate of 7cals/cm²s. At a temperature of 727⁰C, the rate of heat radiated in the same units will be:
Options
(a) 50 (b) 112 (c) […]
The two ends of a rod of length L and a uniform cross-sectional area
The two ends of a rod of length L and a uniform cross-sectional area A are kept at two temperatures T₁ and T₂ (T₁ > T₂). The rate of heat transfer, dQ/dt through the rod […]
A body takes 5 minute for cooling from 50⁰C to 40⁰C. Its temperature
A body takes 5 minute for cooling from 50⁰C to 40⁰C. Its temperature comes down to 33.33⁰C in next 5 minute. Temperature of surroundings is
Options
(a) 15⁰C (b) 20⁰C (c) 25⁰C (d) 10⁰C
Assuming the sun to have a spherical outer surface of radius r
Assuming the sun to have a spherical outer surface of radius r, radiating like a black body at temperature t⁰C, the power received by a unit surface, (normal to the inicident rays) at a distance […]
An ideal black body is equivalent to
An ideal black body is equivalent to
Options
(a) Hot sodium lamp (b) Tungsten filament (c) Hot lampblack (d) Small hole in a hollow sphere
Correct Answer:
Small hole in a hollow sphere
Explanation: […]