Solve problems involving electric field strength using 𝐸 = 𝐹 𝑄 = 1 4𝜋𝜀𝑜 𝑞 𝑟2 = 𝑘𝑞 𝑟2.

Two point charges, P and Q, are separated by different distances in separate trials. The electric field strength at a test location is measured for each trial. Which statement correctly compares the relationship between electric field strength and distance for the two charges?

A point charge of +8.0 × 10⁻⁶ C is placed at point P in a region of uniform electric field. The charge experiences a force of 1.6 N in the direction of the field. Calculate the electric field strength at point P. Show your working.

A point charge of +3.0 nC is placed at position A. The electric field strength at point B, located 2.0 cm from A, is measured as 6.75 × 10⁴ N C⁻¹. When the charge is moved to position C, the field strength at B becomes 1.69 × 10⁴ N C⁻¹. What is the distance from C to B?

A student performs an experiment to investigate the electric field strength at various distances from a point charge. The apparatus consists of a test charge Q = +2.0 × 10⁻⁶ C placed at different radial distances from a fixed source charge. The student measures the electrostatic force on the test charge at each position using a calibrated force sensor. The results are shown in the table below. What is the magnitude of the source charge producing this field?