Easy Tutorial
For Competitive Exams
NEET - Physics Radiation Practice Q & A Page: 4
26314.A body at higher temperature T K radiates heat at a rate which is proportional to
T
T2
T–4
T4
26315.According to Prevost’s theory of heat exchange, the heat exchange shops at
0°C
– 5°C
– 273°C
– 273 K
26316.The best ideal black body is
Lamp of charcoal heated to high temperature
Metal coated with a black dye
Glass surface coated with coalter
Hollow enclosure blackened inside and having a small hole
26317.The rate of cooling of a body is 0.5°C/minute, when the body is 50°C above the surrounding. What is the rate of cooling if the body is 30°C above the surrounding?
24°C/hour
18°C/hour
30°C/hour
12°C/hour
26318.Coefficient of transmission and coefficient of reflection for a given body are 0.22 and 0.74 respectively. Then, at a given temperature, the coefficient of emission for the body is
0.4
0.04
0.96
0.22
26319.Wien’s constant units is
m.k
kg
m.m
mg.
26320.A body radiates heat at the rate of 4 cal/m2/s, when its temperature is 227°C. what is the heat radiated by the same body when its temperature is 727°C?
8 cal/m2/s
16 cal/m2/s
64 cal/m2/s
32 cal/m2/s
26321.The earth receives at its surface radiation from the sun at the rate of 1400 W/$m^{2}$. The distance of the centre of the sun from the surface of the earth is 1.5 × $10^{11}$ m and the radius of the sun is 7.0 × $10^{8}$ m. Treating sun as a black body, it follows from the above data that its surface temperature is,
5801 K
106 K
50.1 K
2801°C
26322.Two thermometers A and B exposed to sunlight. The value of A is painted black but that of B is not painted. The correct statement regarding this case is
Temperature of B will rise faster
Temperature of A will remain more than B
Both of A and B show equal rise from the beginning
Temperature of A will rise faster than B but the final temperature will be same in both
26323.Two spheres made of same material have radii in the ratio 2: 1. if both the spheres are at same temperature, then what is the ratio of heat radiation energy emitted per second by them?
1: 4
4: 1
3: 4
4: 3
26324.The temperature of a black body is gradually increased. The colour of the body will change from
White-green-red
Red-yellow-blue
Red-violet-yellow
Yellow-green-red
26325.A black body at hot temperature at 227°C radiates heat at a rate of 5 cal/$cm^{2}$s. at a temperature of 727°C the rate of heat radiated per unit area will be
50 cal/$cm^{2}$s
250 cal/$cm^{2}$s
80 cal/$cm^{2}$s
100 cal/$cm^{2}$s
26326.Radiation emitted by a surface is directly proportional to
Third power of its temperature
Equal to its temperature
Twice power of its temperature
Fourth power of its temperature
26327.A body radiates heat at the ate of 5 cal/m2-s when its temperature is 227°C. the heat radiated by the same body when its temperature is 727°C is
10 cal/m2-s
20 cal/m2-s
40 cal/m2-s
80 cal/m2-s
26328.Which one of the following constants is not related to radiation?
Solar constant
Stefan’s constant
Boltzmann’s constant
Wien’s constant
26329.Rate of cooling of body is 0.5°C/min, when the system is 50°C above the surroundings. When a system is 30°C above the surroundings, the rate of cooling will be
0.3°C/min
0.6°C/min
0.7°C/min
0.4°C/min
26330.According to Wien’s law
λm T = constant
$\dfrac{\lambda_{m}}{T}$ = constant
$\dfrac{T}{\lambda_{m}}$ = constant
T + λm = constant
26331.The sun emits light with a maximum wavelength of 510 nm while another star X emits light of maximum wavelength of 350 nm. What is the ratio of the surface temperatures of the sun and the star?
0.35
1.5
1.1
0.69
26332.A sphere cube and a thin circular plate all made of the same material and having the same mass are initially heated to a temperature of 300°C. which of these cools fastest?
Sphere
Cube
Plate
None of these
26333.A black body emissive power is 81 J/m2 sec it is at 300 K another one ordinary body emissivity is 0.8 it is at 500 K then what is the emissive power of ordinary body?
200 J/m2sec
300 J/m2 sec
400 J/m2 sec
500 J/m2 sec
Share with Friends