Explain the follo characteristics of semi-conductors: a. Photo electric effect b. Thermoelectric effect c. Communicating action d. Hall effect

Vodafone UA ADYM 3G 64 I 10:00 PM Electricity_2.pdf ELECTRIC CURRENT. PHYSIOLOGICAL EFFECT OF CURRENT 1. The electric field E is defined to be E =, where F is the electrostatic force exerted on a small q' positive test charge q . E has units of N/C. 2. In uniform electric field the potential difference is AV = Ed, where E is electric field and d is the distance from A to B, or the distance between the plates. 3. A capacitor is a device used to store charge. The amount of charge q a capacitor can store depends on two major factors - the voltage applied and the capacitor's physical characteristics, such as its size. The capacitance C is the amount of charge stored per volt, or C = , units Farad (F). 4. Capacitance of a parallel plate capacitor C = , where ɛ, = 8.85 · 10-12 F/m is called the εερΑ permittivity of free space, & is the dielectric constant of the material, A is area of plates and d is distance between plates. 5. Capacitors are used in a variety of devices, including…

1. A cell membrane is 7.0 nm thick, with a 70 mV potential difference across the membrane. What is the electric field strength inside the membrane?

Most wires that are good conductors are wrapped in an insulator to keep people from being shocked when they touch them.