Question

You have built a device that measures the temperature outside and displays it on a dial as a measure of how far away from room temperature outside is. The way the dial works is that a needle with a charged ball on the end is placed between two charged parallel plates. The strength of the uniform electric field between the plates is proportional to the outside temperature. Given that the charged ball on the needle has a charge of-2.4 μC and the needle can be represented as a string with tension 0.350 N, and is at an angle of 12°, consider the following 01 -90 mg free-body diagram What is the mass of the object? What is the magnitude of the electric field? N/C

Answer 1

T Cos theta = mg T Sin theta = QE 0.350 Cos 12 degree = m times 9.8 M = 0.03493 kg = 34.93 gm Right arrow 0.350 Sin theta = q times E E = 0.350 mm 12 degree/2.4 times 10^-6 = 3.03 times 10^4 N/C