The sun is its highest in the sky during what season

One day, after pulling down your window shade, you notice that sunlight is passing through a pinhole in the shade and making a small patch of light on the far wall. you see that the patch of light seems to be a circular diffraction pattern. it appears that the central maximum is about 1 cm across and you estimate that the distance from the window shade to the wall is about 3 m. what is (a) the average wavelength of sunlight? (b) the diameter of the pinhole?

Acharge q experiences no net force at a particular point in space. which of the following situations described below must always be true? -there are no other charges nearby. -if there are other charges nearby, they must all have the same sign as q. -if there are other charges nearby, they must all have the opposite sign of q. -if there are other charges nearby, the total positive charge must equal the total negative charge. -none of the above

Roger pushes a box on a 30° incline. if he applies a force of 60 newtons parallel to the incline and displaces the box 10 meters along the incline, how much work will he do on the box? a. 5.2 × 102 joules b. 6.0 × 102 joules c. -5.2 × 102 joules d. -6.0 × 102 joules