Answer:
The wavelength is 
Explanation:
From the question we are told that
The thickness is 
The refractive index of the non-reflective coating is
The refractive index of glass is 
Generally the condition for destructive interference is mathematically represented as

Where
is the angle of refraction which is 0° when the light is strongly transmitted
and n is the order maximum interference
so

at the point n = 1



at n =2




Now we know that the wavelength range of visible light is between

So the wavelength of visible light that is been transmitted is

Answer:
3 A
Explanation:
Charge is a product of current and time, expressed as Q=It where Q is charge in Coulombs, I is current in Amperes and t is time taken in seconds. Making I the subject of the formula then 
Substituting 120 C for charge and 40 s for t then
From the choices given, it appears that time should have been 4 s to get option A or alternatively charge should have been 1200 C
Your answer would be D- Knowledge of the environment.
I hope this helped... ;)
At the top most position when ball reach to height 31 m
The speed of the ball must be ZERO
now we can use kinematics to find the final speed of the ball when it will hit back the ground
the equation of kinematics will be




so it will hit the ground at speed 24.65 m/s
Answer:
f>1000Hz and wavelength=0.343 m
Explanation:
We are given that
Frequency of stationary siren,f=1000 Hz
Wavelength of stationary sound,
When a observer is moving towards the siren then the frequency increases.
Therefore,an observer who is moving towards the siren measure a frequency >1000 Hz.
The wavelength depends upon the speed of source.
But we are given that siren is stationary.
Therefore, source is not moving and then the wavelength remains same.
f>1000Hz and wavelength=0.343 m