First you find the frequency which is. 1/T(period) so u get 1*10^10
Now that you know frequency u can solve for speed: s= wavelength* frequency, but don't forget to convert 3cm into meters: 3/100= .03m so now you do (1*10^10)(.3)= 300,000,000 m/s or 3*10^8 m/s
Hope this helped :))
Picture? I may be able to answer if you have a chart or some kind of graph as a referral to the question
Answer:
The stress is 
Explanation:
From the question we are told that
The diameter of the post is 
The length is 
The weight of the loading mass
Generally the radius of the post is mathematically represented as

=> 
Generally the area of the post is

=> 
=> 
Generally the weight exerted by the load is mathematically represented as

=> 
=> 
Generally the stress is mathematically represented as

=> 
=> 
Answer:
The wavelength is 
Explanation:
From the question we are told that
The wavelength of the first light is 
The order of the first light that is being considered is
The order of the second light that is being considered is
Generally the distance between the fringes for the first light is mathematically represented as

Here D is the distance from the screen
and d is the distance of separation of the slit.
For the second light the distance between the fringes is mathematically represented as

Now given that both of the light are passed through the same double slit

=> 
=> 
=> 
=> 