An electromagnet is a device in which moving electric charges (current) in a coil of wire create a magnet. what’s one advantage of using electromagnets in devices?

1.electromagnets have a strong, constant magnetic field.

2.electromagnets are more powerful than permanent magnets.

3.electromagnets don’t need a source of electricity to work.

4.electromagnets can easily be turned on and off.

Which surface feature of the moon is characterized by mountainous areas? terrae craters maria regolith

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?

Agas is contained in a vertical, frictionless piston–cylinder device. the piston has a mass of 3.2 kg and a cross-sectional area of 35 cm2. a compressed spring above the piston exerts a force of 190 n on the piston. if the atmospheric pressure is 95 kpa, determine the pressure inside the cylinder.