Answer: 430 nm.
Explanation:
The relation of wavelength and frequency is:
Formula used : 
where,
= frequency =
= wavelength = ?
c = speed of light = 
Now put all the given values in this formula, we get
Thus the wavelength (in nm) of the blue light emitted by a mercury lamp is 430 nm.
Although scientists can't detect or observe black holes with telescopes that detect x-rays, light, or other many other different forms of electromagnetic radiation and waves. But they can detect and study them by the effect of matter near it. If a black hole passes through a cloud of interstellar matter, it will draw matter inward (this process is known as accretion). A similar process occurs when a star passes through a black hole. When this happens, a star can break apart as it pulls it self toward it. As the attracted matter accelerates and starts heating up, it emits x-rays that are radiate into space.
Recent studies do show that black do have a very big influence towards neighborhoods around it. The black hole emits gamma ray bursts, devouring nearby stars, and spurring the growth of new stars in some areas while stalling it in others.
Info: https://science.nasa.gov/astrophysics/focus-areas/black-holes
Hope this Helps! (:
Answer:
(a) 
(b) The charge inside the shell is placed at the center of the sphere and negatively charged.
Explanation:
Gauss’ Law can be used to determine the system.
This is the net charge inside the sphere which causes the Electric field at the surface of the shell. Since the E-field is constant over the shell, then this charge is at the center and negatively charged because the E-field is radially inward.
The negative charge at the center attracts the same amount of positive charge at the surface of the shell.
Here (X) is a parallel combination of resistors whereas it is series combination of resistors in (Y).
Hope this is the answer you're looking for. If it is correct then mark my answer as the brainliest! :)
