00:01
Work function for the goal is given in the question as q is equal to 5 .10 electron volts.
00:11
In the first equation, they ask to find the work function of the gold from electron volts to joules.
00:20
So q is equal to 5 .10 electron volts.
00:25
One electron value 1 .6 into 10 to the power of minus 19 joules.
00:31
So by multiplying this we got 3 .16 into 10 to the power of minus 90 joules.
00:42
The second question, they asked to find the cutoff frequency.
00:51
For cutoff frequency, charge is equal to n f.
00:55
When n is the number of electrons, f is the frequency.
00:59
So that implies cutoff frequency is equal to charge by number of electrons.
01:08
Charge already we calculated that 3 .16 into 10 to the 10 to the power of minus 19 joules by number of electrons in one unit of charge that is 6 .625 into 10 to the power of minus 34 so by doing the calculation we got 1 .23 into 10 to the power of 15 heads.
01:42
So this is the cutoff frequency of the...
01:47
In the third question, they ask to calculate the maximum wavelength of light incident on a goal to release the photo electrons from the surface.
01:58
For that sake, the frequency is equal to...
02:06
Cutoff frequency is equal to speed of light divided by wavelength and that cutoff frequency already we calculated that is 1 .2 3 into 10 to the power of 15 is equal to see that is this light speed 3 into 10 to the power of 8 meter per second divided by lambda nothing but a wavelength...