# surfaces

1. ### radius of equipotential surfaces

Hi, I am doing my physics homework and I cannot do this problem. Can anyone please help me. The question is A metal sphere of radius 0.40 carries a charge 0.50 . Equipotential surfaces are to be drawn for 100- intervals outside the sphere. Determine the radius r of the first. Determine the...
2. ### refraction at plane surfaces

a glass sphere in the shape of a quarter - cylinder lies on ahorizontal table . a uniform , horizontal light beam falls on its vertical plane surfaces, as shown in the figure . if the radius of the cylinder is R = 5 cm and the refractive index of the glass is n = 1.5 . where , on the table...
3. ### Horizontal vs Vertical Surfaces with Friction

When pushing an object such as a book across a horizontal surface such as a table, my book says the following: μ = Ff/FN where: μ: coefficient of friction Ff: force of friction FN: Normal force I understand the above very well but my book did not explain how friction acts along a vertical...
4. ### Why do shiney surfaces condense first?

Say,.. in a shower room, why do glossy or shiny surfaces condense first? Does this have to do with radiant energy bouncing off these surfaces making it a bit cooler or to other reasons? I remember the grade School "experiment" to find the dew point using a "shiny" metal container. Why does it...