Final answer:
The strength of the electric field formed by a charged rod with a linear charge density of 120 C/m at a distance of 80 cm on the central axis is 1.35 × 10^11 N/C.
Step-by-step explanation:
The electric field strength formed by a charged rod can be calculated using the formula:
E = k * λ / r
Where E is the electric field strength, k is Coulomb's constant (9 × 10^9 N m^2/C^2), λ is the linear charge density of the rod in C/m, and r is the distance on the central axis from the rod.
In this case, the linear charge density is given as 120 C/m and the distance is 80 cm. Converting the distance to meters, we have r = 0.8 m.
Substituting these values into the formula:
E = (9 × 10^9 N m^2/C^2) * (120 C/m) / 0.8 m = 1.35 × 10^11 N/C
Therefore, the strength of the electric field is 1.35 × 10^11 N/C.