What type of electromagnetic radiation is associated with the peaks in this spectrum?

The speed of light can be used to measure the

The illuminance of a surface varies inversely with the square of its distance from the light source. if the illuminance of a surface is 120 lumens per square meter when its distance from a certain light source is 6 meters, by how many meters should the distance of the surface from the source be increased to reduce its illuminance to 30 lumens per square meter?

Aball is thrown vertically upwards from the top of a tower with a speed of 100m/s. it strikes the pound near the base of the tower after 25sec . the height of the tower is