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Two spherical black bodies of radius r1 and r2 with surface temperature T1 and T2 respectively, radiate same power, then r1 : r2 is ______.
Concept: undefined >> undefined
The speed at which the flow of water in a long cylindrical pipe of diameter 6 cm becomes turbulent is ______
(The viscosity of water = 1 x 10-3 Pa.s and for the onset of turbulent flow in a long cylindrical pipe, Reynolds number = 3000)
Concept: undefined >> undefined
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Reynold's number is less for ______.
Concept: undefined >> undefined
The radiation energy density per unit wavelength at a temperature T has a maximum at a wavelength `lambda_0.` At temperature 4T, it will have a maximum at a wavelength ____________.
Concept: undefined >> undefined
A blackbody emits radiations of maximum intensity at a wavelength of 6000 A, when the temperature of the body is 1227 °C. If the temperature of the body is increased by 2227 °C, the maximum intensity of emitted radiation would be observed at ______.
Concept: undefined >> undefined
A blackbody is at a temperature of 5760 K. The energy of radiation emitted by the body at wavelength 250 nm is U1, at wavelength 500 nm is U2 and that at 1000 nm is U3. Wien's constant, b = 2.88 x 106 nmK. Which of the following is correct?
Concept: undefined >> undefined
At a fixed wavelength, the `"E"_lambda` - T graph for an ideal blackbody is ____________.

Concept: undefined >> undefined
Water is flowing through a tube of diameter 1 cm at 6 cm/s. Taking `eta` = 10-2 poise the flow of liquid and Reynold's number are ____________.
Concept: undefined >> undefined
The maximum average velocity of water in a tube of diameter 4 cm so that the flow becomes laminar is [Viscosity of water is 10-3 N m-1, take Rn = 200] ____________.
Concept: undefined >> undefined
The colour of a star depends upon its ____________.
Concept: undefined >> undefined
A solid sphere rolls down from top of inclined plane, 7m high, without slipping. Its linear speed at the foot of plane is ______. (g = 10 m/s2)
Concept: undefined >> undefined
A solid sphere of mass 1 kg and radius 10 cm rolls without slipping on a horizontal surface, with velocity of 10 emfs. The total kinetic energy of sphere is ______.
Concept: undefined >> undefined
The Reynold's number for a liquid flow in a tube does NOT depend on ______.
Concept: undefined >> undefined
A man is supported on a frictionless horizontal surface. It is attached to a string and rotates about a fixed centre at an angular velocity `omega`. The tension in the strings is F. If the length of string and angular velocity are doubled, the tension in string is now ____________.
Concept: undefined >> undefined
About black body radiation, which one of the following is 'WRONG' statement?
Concept: undefined >> undefined
The power (P) is supplied to rotating body having moment of inertia 'I' and angular acceleration 'α'. Its instantaneous angular velocity is ______.
Concept: undefined >> undefined
A ring and a disc roll on horizontal surface without slipping with same linear velocity. If both have same mass and total kinetic energy of the ring is 4 J then total kinetic energy of the disc is ______.
Concept: undefined >> undefined
A solid sphere is rolling on a frictionless surface with translational velocity 'V'. It climbs the inclined plane from 'A' to 'B' and then moves away from Bon the smooth horizontal surface. The value of 'V' should be ______.

Concept: undefined >> undefined
The angular velocity of minute hand of a clock in degree per second is ______.
Concept: undefined >> undefined
Solid spherical ball is rolling on a frictionless horizontal plane surface about is axis of symmetry. The ratio of rotational kinetic energy of the ball to its total kinetic energy is ______.
Concept: undefined >> undefined
