Light is shining perpendicularly on the surface of the earth with an intensity of 680 W/m2. Assuming that all the photons in the light have the same wavelength (in vacuum) of 681 nm, determine the number of photons per second per square meter that reach the earth.

The speed of light can be used to measure the

Question 1 (5 pts): what is the maximum distance for which you can you resolve the two individual headlights of an on-coming truck as two separate lights rather than one if the headlights are separated by 2.00 m and your eye has a diameter of 1.00 centimeter? assume a wavelength of 500 nm.

Under the action of a constant force an object accelerates at 7.8 m/s2. what will the acceleration be if (a) the force is halved? (b) the object's mass is halved? (c) the force and the object's mass are both halved? (d) the force is halved and the object's mass is doubled?