What happens when any ray of light strikes a concave mirror, after passing through its focal point?
a)the reflected ray travels parallel to the vertex.
b)the reflected ray passes through the principal axis.
c)the reflected ray passes through the center of curvature.
d)the reflected ray travels parallel to the principal axis.

Option (D)

Explanation:

The rules to draw the ray diagrams for concave mirror are given below:

1. When a ray of light incident on the pole of concave mirror at an angle of incidence, then after reflection, the angle of incidence is equal to the angle of reflection.

2. When incident ray of light passes through the centre of curvature of the mirror, then the reflected ray retraces its path.

3. When the incident ray of light passing through the focus of the concave mirror, then after reflection the reflected ray becomes parallel to the principal axis and vice versa.

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