The lamps in circuit drawn below are all identical, Each of the cells have a potential difference of 1.5 volts What is the potential difference across the 3 cells that are joined in series

4.5V

Explanation:

In a arrangement of cells, the cells could be joined end to end(series) or to a common junction (parallel).

When cells are joined in series, the total emf of the cell is the sum of the individual emf of all the cells.

Hence;

Total emf = 1.5V + 1.5V + 1.5 V = 4.5 Volts

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