Why correction of curvature is always considered as a negative?
Demolition is defined as simply the safe and careful removal of existing buildings & structures in order to utilise the land for another use. The several methods for the demolition of any structure are as follows ; Total Demolition : It refers to the demolition of an entire building or structureRead more
Demolition is defined as simply the safe and careful removal of existing buildings & structures in order to utilise the land for another use.
The several methods for the demolition of any structure are as follows ;
- Total Demolition : It refers to the demolition of an entire building or structure. In case of community re-structure, this is the most common method.
- Interior Demolition : This method refers to the demolition of interior part of the building, while protecting and maintaining the exterior structure. For example; partition walls, ceilings, etc. This method is one of the great option for creating more space inside the building by removing the troubling areas.
- Selective Demolition : This method refers to the removing of specific parts of the building. In case if there is a old building which is not performing as it should & the entire building is not a state of concern. Or perhaps it is a listed building, therefore it may be restricted as to what and how much you can demolish. So you could select a particular section of a building to demolish and build up from scratch.
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Here, consider lens or mirror at the origin. Now, all the distances measured in the direction of incident rays are positive and distances measured in the direction opposite to the direction of incident rays are negative. All distances have to be measured from the lens or mirror. For example object dRead more
Here, consider lens or mirror at the origin. Now, all the distances measured in the direction of incident rays are positive and distances measured in the direction opposite to the direction of incident rays are negative. All distances have to be measured from the lens or mirror. For example object distance measured from lens or mirror is measured in the direction opposite to direction of incident rays hence, in these case object distance u is negative. The paraxial parallel rays are focused on the right hand side of convex lens. See, this distance f is measured in the direction of incident rays . Hence, focal length of convex lens is positive. But, we can see that focal length of concave mirror is negative. It’s radius of curvature is also negative. The radius of curvature of first surface of convex lens is positive, but radius of curvature of it’s second surface is negative. You can see that radius of curvature and focal length of concave mirror are negative.
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