00:01
Hi, in this question we need to find out frequency and wave number when wavelength is given first.
00:05
So wavelength is lambda, frequency is nu which is equal with c by lambda.
00:10
C is velocity of light in air medium.
00:14
In si unit it is 3 into 10 to the power 8 meter per second.
00:20
Lambda in angstrom in meter it would be 2 .56 into 10 to the power minus 10 meter.
00:27
2 .56 into 10 to the power minus 10 meter.
00:31
Meter meter will be cancelled out.
00:32
We know one second inverse is equal with one hertz.
00:35
So we will get frequency in hertz that would be 1 .17 into 10 to the power 18 hertz.
00:43
Next we need to find out wave number.
00:45
Wave number is nu bar which is equal with 1 by lambda.
00:50
So putting this value here we will get wave number as 3 .90 into 10 to the power 9 meter.
00:57
Next we have given frequency is equal with 250 megahertz which is equal with 250 into 10 to the power 6 hertz or second inverse.
01:10
Energy in joule can be find out from the formula.
01:14
Planck's constant that is h into nu equal to value of planck's constant is 6 .626 into 10 to the power minus 34 joule second.
01:24
Nu is 250 into 10 to the power 6 second inverse.
01:29
Second inverse second will be cancelled out equal to 1 .65 into 10 to the power minus 25 joule.
01:37
Next we need to find out lambda in centimeter.
01:40
This is equal with c by nu.
01:46
So c is 3 into 10 to the power 8 meter per second...