Which semiconductors are used in each of the three parts of a pnp transistor?
the base and the emitter are p-type, and the collector is n-type.
the emitter and the collector are n-type, and the base is p-type.
the base and the collector are p-type, and the emitter is n-type.
the collector and the emitter are p-type, and the base is n-type.

At 20∘c, the hole in an aluminum ring is 2.800 cm in diameter. you need to slip this ring over a steel shaft that has a room-temperature diameter of 2.804 cm . 1. to what common temperature should the ring and the shaft be heated so that the ring will just fit onto the shaft? coefficients of linear thermal expansion of steel and aluminum are 12×10−6 k−1 and23×10−6 k−1 respectively.