Answer:
Explanation:
Given
rope makes an angle of 
Mass of sled and snow is m
Normal Force 
applied Force is F
as Force is pulling in nature therefore normal reaction is given by

Also 


-------1
---------2
Squaring 1 & 2 and then adding


Substitute value of F in 1


Distance traveled by him = circumference of that circular path = 2πr = 2π(3.5)
= 7π = 7×3.14 = 21.98 m
time = 8.9 s [ Given ]
Now, Average speed = distance / time
s = 21.98 / 8.9
s = 2.46 m/s
Hope this helps!
Answer:
Explanation:
This problem relates to interference of light in thin films .
The condition of bright fringe in thin films which is sandwitched by two layers of medium having lesser refractive index is as follows.
2nt = (2n+1) λ / 2 , n is refractive index of thin layer , t is its thickness , λ is wavelength of light .
2 x 1.5 t = λ / 2 , if n = 0 for minimum thickness.
2 x 1.5 t = 600 / 2 nm
t = 100 nm .
Higher frequency,higher energy,shorter wavelength
Answer
The answer for the first one I think is false.
The second one would be true i think. I hope i got it right and have a wonderful day