Look at the picture of the thermos flask and answer the following question

The outer surface of the inner wall of a thermos flask has a very shiny surface. What effect will this have on heat escaping from a hot liquid inside a thermos flask?

Look at the picture of the thermos flask and answer the following question What is the role of silver coating on the outer wall in the flask?

Look at the picture of the thermos flask and answer the following question Would you expect the cork to be a good or a bad conductor of heat?

Look at the picture of the thermos flask and answer the following question Which means of heat transfer are prevented by having a vacuum between the two walls of thermos flasks?

The vacuum kept in between the walls of a thermos flask reduces the heat transfer by :

What type of systes are the following system? Hot tea placed in a thermos flask.

''A hot liquid' remains hot and a cold liquid remains cold in a thermos flask.'' Explain how ?

Air is bad conductor of heat or partly conducts heat, still vacuum is to be placed between the walls of the thermos flask because

We have a disc of neglligible thickness and whose surface mass density varies as radial distance from centre as sigma=sigma_(0)(1+r/R) , where R is the radius of the disc. Specific heat of the material of the disc is C . Disc is given an angular velocity omega_(0) and placed on a horizontal rough surface such that the plane of the disc is parallel to the surface. Coefficient of friction between disc and suface is mu . The temperature of the disc is T_(0) . Answer the following question on the base of information provided in the above paragraph If the kinetic energy lost due to the friction between disc and surface is absorbed by the disc the moment heat is generated, by the mass lying at the point where the energy is lost. Assume that there is no radial heat flow in betwen disc particles. Rate of change in temperature at a point lying at r distance away from centre with time, before disc stops rotating, will be ( alpha -magnitude of angular acceleration of rod)

A ball is projected on a very long floor. There may be two conditions (i) floor is smooth & (ii) the collision is elastic If both the considered then the path of ball is as follows. Now if collision is inelastic and surface is rough then the path is as follows. Successive range is decreasing . Roughness of surface decreases the horizontal component of ball during collision and inelastic nature of collision decreases the vertical component of velocity of ball. In first case both components remain unchanged in magnitude and in second case both the components of the velocity will change. Let us consider a third case here surface is rough but the collision of ball with floor is elastic. A ball is projected withe speed u at an angle 30^(@) with horizontal and it is known that after collision with the floor its speed becomes (u)/(sqrt(3)) . Then answer the following questions. If the ball after first collision with the floor has rebounded vertically then the speed of the ball just after the collision with the floor would have been :

The diagram below represents an experiment to demonstrate a particular aspect of a physiological process in plants. Study the diagram and answer the questions that follows: What is the chemical substance named X in the diagram? What is the special condition created inside the flask due to the presence of the substance X?