Answer:
Option C and D only
Explanation:
Option A is incorrect because refractive index of a material is the ratio of speed of light in vacuum to the speed of light in a any given medium
Option B is correct as the speed of light in vacuum is always greater than the speed of light in any given medium.
Option C is correct
Option D is incorrect
Option E is incorrect because the denser the medium the more is the refractive index. Water is denser than air, hence it should have more refractive index as compared to that of air.
Answer:
Red photons have the least amount of energy
Explanation:
The relationship between the photon energy and the color of light is given by:
where
E is the energy
h is the Planck constant
c is the speed of light
is the wavelength (which determines the color of light)
As we see from the equation, energy and wavelength are inversely proportional: this means that the longer the wavelength, the lower the energy, and viceversa.
Among the colors in the visible light spectrum, red is the color with longest wavelength (620-750 nm) and violet is the color with shortest wavelength (380-450 nm). This means that red photons have the least amount of energy, while violet photons have the greatest amount of energy.
So the correct choice is
Red photons have the least amount of energy
Answer:
&
Explanation:
Given:
- interior temperature of box,
- height of the walls of box,
- thickness of each layer of bi-layered plywood,
- thermal conductivity of plywood,
- thickness of sandwiched Styrofoam,
- thermal conductivity of Styrofoam,
- exterior temperature,
<u>From the Fourier's law of conduction:</u>
....................................(1)
<u>Now calculating the equivalent thermal resistance for conductivity using electrical analogy:</u>
.....................(2)
Putting the value from (2) into (1):
is the heat per unit area of the wall.
The heat flux remains constant because the area is constant.
<u>For plywood-Styrofoam interface from inside:</u>
&<u>For Styrofoam-plywood interface from inside:</u>
Answer:
its direction is changing
Answer:
0.00903 rad
0.00926 rad
6.268\times 10^{-6}
Explanation:
s = Diameter of the object
r = Distance between the Earth and the object
Angle subtended is given by
For the Moon
The angle subtended by the Moon is 0.00903 rad
For the Sun
The angle subtended by the Sun is 0.00926 rad
Area ratio is given by
The area ratio is