The following examples use the Orders table to show how the positive and negative unary operators function. When a positive unary operator is set against a negative value, the returned value is negative (positive_value * negative_value = negative_value). When a negative unary operator is set against a negative value, the returned value is positive (negative_value * negative_value = positive_value). Copy. SELECT (DATEPART(day, Order Date) - DATEPART(day, Shipped Date)) FROM Orders WHERE OrderID = '10248' -- Without a unary operator, the value returned is '-12'.
Inmersion oil does not increase magnification. Inmersion oil is needed at high magnifications. Why? High magnifications come with high numerical appertures (although one can have a low-magnification high-numerical apperture objective). High numerical appertures are required to capture more light and improve resolution.
The magnification of a microscope describes the increase in apparent size of an object compared with its actual size. An object magnified 10 times (10X) appears 10 times larger than it really is. Total magnification is the product of the ocular lens magnification and the objective lens magnification. Magnification does not describe the quality of the image. Magnifying an object without good resolution is called empty magnification, as the image appears larger but no greater detail can be seen.