Final answer:
The intensity of the electric field midway between two point charges can be calculated using the formula E = k(|q1| + |q2|) / r^2, where k is Coulomb's constant, |q1| and |q2| are the magnitudes of the charges, and r is the distance between the charges.
Step-by-step explanation:
The electric field intensity E between two point charges can be calculated using the formula:
E = k(|q1| + |q2|) / r^2
where k is the Coulomb's constant (8.99 x 10^9 Nm^2/C^2), |q1| and |q2| are the magnitudes of the charges (in this case, 20 microC and 8 microC respectively), and r is the distance between the charges (20 cm or 0.2 m).
Plugging in the values, we get:
E = (8.99 x 10^9 Nm^2/C^2)(20 x 10^-6 C + 8 x 10^-6 C) / (0.2 m)^2
E = (8.99 x 10^9 Nm^2/C^2)(28 x 10^-6 C) / (0.2 m)^2
E = (8.99 x 10^9 Nm^2/C^2)(28 x 10^-6 C) / 0.04 m^2
E = (8.99 x 10^9 Nm^2/C^2)(28 x 10^-6 C) / 0.04
E = (8.99 x 10^9)(28 x 10^-6) / 0.04 N/C
E = 6.295 x 10^6 N/C
Therefore, the intensity of the electric field E midway between the two charges is 6.295 x 10^6 N/C.