00:01
Hello, lenore, let's solve this problem.
00:03
I have displayed a schematic diagram of this kirsten.
00:08
Yeah, from the kirsten itself, we can have an idea that the angle of incidence is 58 degree and the depth of the lake is 2 .9 meter and b is a point vertically below or directly below the point a.
00:31
And there are two cases.
00:32
We have to solve one if the light does not refract it's clear that light is traveling from air to water so obviously a rarer to denser medium there should be a refraction but because it has two parts one if there is no refraction which means if there is no bended light where will be the how far away from the point be would the laser beam strike at the lake of the bottom lake.
01:07
Well, if there is no bend in the light happens, then what will happen? the light will likely travel to, sorry, it will travel like this.
01:28
So what will be this distance? this is suggesting.
01:36
We know that if there is no bend in light, then the angle of incidence will be the angle of refraction here because they are opposite angles right this is 58 degree obviously this one is going to be 58 degree okay now look at this triangle a b let this be c triangle a bc this one is 58 we have to find this distance right which means bc how we can find bc from this if we take tan tan of angle a then tan is equal to opposite side by adjacent side bc by ab bc is the distance that we are going to find so bc is equal to tan 58 into a b a b is already given which is the depth of the league so tan fifty eight is equal to 1 .60 into ab is equal to 2 .9 and the answer is 4 .64 meter.
03:04
So the laser will strike at a distance 4 .64 meter away from the point b...