Changing from low power to high power increases the magnification of a specimen. The amount an image is magnified is equal to the magnification of the ocular lens, or eyepiece, multiplied by the magnification of the objective lens. When you switch to a higher power, the field of view is closes in. You will see more of an object on low power. The depth of focus is greatest on the lowest power objective. Each time you switch to a higher power, the depth of focus is reduced. "It really depends on your microscope but I will answer your question based on the most common microscope specifications: Low power is the 10x objective lens so it provides 100x total magnification. The high power lens is the 40x lens so it provides 400x total magnification.