The star P Cygni (in the constellation Cygnus, the Swan) is surrounded by an extensive low-density atmosphere. It has a bright, continuous spectrum with many narrow, dark absorption lines and a few bright emission lines. The bright, continuous part of the spectrum is produced by:.
a) all parts of the star, the stellar surface and the atmosphere, equally.
b) only the part of the low-density atmosphere that is between us and the surface of the star.
c) the hot, dense, opaque gas of the star's surface.
d) the hot, low-density atmosphere of the star emitting light in all directions.

b) only the part of the low-density atmosphere that is between us and the surface of the star.

Explanation:

Since in the case of the stars, the photons that are received are not directly from the nucleus, but those that have traveled hundreds of thousands of years to reach the stellar atmosphere. Due to the stars are not at homogeneous temperature, density and pressure, but have gradients in different layers because of the nuclear reactions, superficial gravity or to their constant exchange of heat with their surroundings in an attempt to reach the thermodynamic equilibrium, the continuum observed in the stellar spectra comes from the inner layer of the photosphere.

electromagnetic shielding is the practice of reducing the electromagnetic field in a space by blocking the field with barriers made of conductive or magnetic materials. shielding is typically applied to enclosures to isolate electrical devices from their surroundings, and to cables to isolate wires from the environment through which the cable runs. electromagnetic shielding that blocks radio frequency electromagnetic radiation is also known as rf shielding.

the shielding can reduce the coupling of radio waves, electromagnetic fields and electrostatic fields. a conductive enclosure used to block electrostatic fields is also known as a faraday cage. the amount of reduction depends very much upon the material used, its thickness, the size of the shielded volume and the frequency of the fields of interest and the size, shape and orientation of apertures in a shield to an incident electromagnetic

from wikipedia

answer: 31, 5556. 952 seconds