Answer:
The wavelength will be 4 cm, frequency will be 4.66 Hz and wave speed is 18.6 cm/sec
Explanation:
Given:
No. of crest = 13
No. of trough = 15
Time = 3 seconds
Hence, 1 crest or 1 trough = 
therefore,
13 C + 15 T = 
=
Time given 3 seconds
= 

2 cm distance is travelled is time period

Again wave will travel in 1 T = 4 cm
wave speed v =
= 
= 18.6 cm/s
When a parallel beam of light passes through a convex lens, the rays become farther from one another when the come out. This process of rays is called ''to diverge''. The concave lens makes rays of light diverge, so it is called diverging lens.
Answer:
So, the correct answer is <em><u>the strong nuclear force</u></em>. It actually pulls together nuetrons and protons that are in the nucleus. At very tiny distances only, like those inside the nucleus, so, this strong force succeded in dealing with the electromagnetic force, and it basically stops the electrical repulsion of protons from blowing apart the nucleus.
<u><em>Mark as brainlies please, I need a few more :D</em></u>