Platinum has a work function (also called binding energy) of 9.05 × 10-19 j. which is the longest wavelength that could cause emission of electrons? 2.196 × 106 m 5.654 × 102 m 2.196 × 10-7 m 1.37 × 1015 m 4.553 × 10-6 m

2,196 10⁻⁷ m

Explanation:

This is a problem of photoelectric effect, which was explained by Einstein, assuming that the light was formed by quanta of energy that collide with the electors and is described by the expression

          = h f -Ф

Where   is the maximum kinetic energy of the expelled electrons h is the Planck constant that is worth 6,626 10-34 J s, f is the radiation frequency and Ф is the material's work function.

For the wavelength of greater wavelength (lower energy) the kinetic energy of the electors must decrease to a minimum of zero.

         0 = hf -Ф

         hf = Ф

         f = Ф / h

         f = 9.05 10-19 / 6,626 10-34

         f = 1,366 10 15 Hz

Now the speed of the wave is related to the wavelength and frequency

        c = λ f

        λ = c / f

        λ = 3 10⁸ / 1,366 10¹⁵

        λ = 2,196 10⁻⁷ m

The result is 2,196 10⁻⁷ m

when two balls of the different masses are dropped from equal height, they reach the ground at the same time .this is because they experience the same acceleration.

the acceleration is independent of mass.

thus when they are dropped they will always maintain the same velocity and travel the same distance (neglect air resistance of course) at the same time.