1 During photosynthesis chlorophyll a absorbs light of 440 n

1. During photosynthesis chlorophyll a absorbs light of 440 nm and emits light of 670 nm.

a) what is the energy in joules of a 440 nm photon?

b) what is the energy in joules of a 670 nm photon?

2. What is the wavelength, nanometers, of a photon that has energy of 6.7 *10^-19 joules?

3. arrange the following in increaing order of energy: radio waves, x-rays, red light from a neon sign, microwaves in your microwave oven, ultraviolet light from a UV lamp.

Solution

As we knw

E= hc/lamda

= 6.6*10^-34* 3*10^8/440*10^-9

= 4.54 *10^-19 J

2. E= hc/lamda

= 6.6*10^-34* 3*10^8/670*10^-9

= 2.98 *10^-19

3. 6.7*10^-19 = hc/lambda

lambda = 298 nm

4.

in the increasing order of energy

1. x-rays

2.Ultravoilet

3. red light frm a neon sign

4.microwave

5.radio wave

Here x-rays r having highest energy

and the rest follow the order given.