Answer:

Explanation:
Given that,
An infrared telescope is tuned to detect infrared radiation with a frequency of 4.39 THz.
We know that,
1 THz = 10¹² Hz
So,
f = 4.39 × 10¹² Hz
We need to find the wavelength of the infrared radiation.
We know that,

So, the wavelength of the infrared radiation is
.
Answer:
0.4A.
Explanation:
Current (A) = Charge (coulomb)/Time (secs)
2 coulombs/5 secs = 0.4A
Answer:
7.5 cm
Explanation:
In the figure we can see a sketch of the problem. We know that at the bottom of the U-shaped tube the pressure is equal in both branches. Defining
Ethyl alcohol density and
Glycerin density , we can write:

Simplifying:

On the other hand:

Rearranging:

Replacing (2) in (1):

Rearranging:

Data:



Answer:
20 hertz of frequency produced.
Explanation:

Here we will find frequency and period should be in second, here given: 0.05 seconds
using the formula:


Answer:
The farther star will appear 4 times fainter than the star that is near to the observer.
Explanation:
Since it is given that the luminosity of the 2 stars is same thus they radiate the same energy per unit time
Consider a spherical wave front of energy 'E' that leaves both the stars (Both radiate 'E' as they have same luminosity)
This Energy is spread over the whole surface area of sphere Thus when the wave front is at a distance 'r' the energy per unit surface area is given by

For the star that is twice away from the earth the distance is '2r' thus we will receive an energy given by
Hence we sense it as 4 times fainter than the nearer star.