Aplane on the ground will weigh:

a)more than a plane in the air
b)less than a plane in the air
c)the same as a plane in the air

On ground weight of plane will be measured as its actual weight which will be given as

now when plane is in air its weight is measured as combined effect of earth gravitational force and buoyancy force both

so weight in air will be given as

here since net effect due to air is opposite to the direction of weight so in air the plane weight will be measure less than its weight on ground.

so answer will be

A)more than a plane in the air

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

conservation of mass

mass before something happens = mass afterwards