Answer:
240 nm
Explanation:
In the interference in thin films , light reflected from upper surface and light reflected from the lower surface of oil are made to interfere each other to form fringes due to path difference of 2μt .
a ) An additional phase shift of 180 ° occurs on the upper surface because light is going from optically rarer medium to denser medium .
b ) There is no such change on reflection from lower surface as light is going from denser to rarer medium ( air ).
c ) For destructive interference the path difference which is equal to 2 μ t should be equal to n λ where n is any number
So for given condition
2 μ t = n λ
For minimum thickness
2 μ t = λ ( n =1 )
t = λ / 2μ
= 600 x 10⁻⁹ /( 2 x 1.25 )
= 240 nm
Answer:black object cools down faster
Explanation: in the space heat transference through radiation. Black objects have more emissivity. Emissivity depends on surface materials properties and very specific on the surface color. Emissivity is close to one for black objects.
Answer:
Explanation:
Given data
At d₁=4.5×10¹⁰m the speed of comet is Vi=9.2×10⁴m/s
At d₂=6×10¹²m the speed will Vf
The work done by surrounding is zero and the energy of system at the initial state equal the energy at final state so we can apply:
Substitute the given values to find final velocity Vf
So