Sunlight reaching the earth

How long does it take for sunlight to reach the earth?

Electromagnetic spectrum

Using the electromagnetic spectrum, estimate the following: 1. the wavelength that separates ultraviolet light from x-rays 2. the wavelength that separates long-wave radio waves from short-wave radio waves.

Light years

An astronomical unit of distance is the light-year, which is the distance light travels in one year. Compute this distance in meters. How many meters away is a star at a distance of 4 light-years from the earth?

Photon frequency and wavelength

A photon has an energy of 2.4eV. Find its frequency and its wavelength.

Photoelectric emission and wavelength

What is the maximum wavelength of light that will lead to photoelectric emission from copper. The work function of copper is 4.5eV.

Maximum kinetic energy

Find the maximum kinetic energy of the photoelectrons ejected from a sodium photoemitter for wavelength 2X10^-7m if the work function of sodium is 2.28eV.

Photons emitted and electomagnetic waves

How many photons are emitted each second by a 1000Watt source that emits electromagnetic waves at the wavelength of 0.05m?

Minimum uncertainty in a proton's velocity

Find the minimum uncertainty in a proton's velocity if this proton is confined in a box of length 5X10^-8m.

Human eye and photon energy

The human eye can detect as few as three photons of 5.5X10^-7m light arriving together. How much energy do these three photons collectively represent?

Work function in electon volts

When a clean zinc surface is irradiated with ultraviolet light, no photoelectrons are emitted from the surface unless the light has a wavelength less than 2.93X10^-7m. Find the work function of zinc in electron volts.