NDA || Physics || Current_Electricity || _Quiz_2020

The input resistance of a transistor is 1 KΩ. For a 20 μA change in the base current, the collector current increases by 1.5 mA. If the voltage gain of the amplifier is 225, find the output resistance.

The resistivities (in Ω m) of a few materials at 0° C is given. Classify them into conductors, insulators or semiconductors.

I (5.7 × 10^-7), II (234.5), III (5.6 × 10⁸), IV (6.3 × 10^-6), V (0.46), VI (3.5 × 10^-5)

Find the resistance of the carbon resistor.

The electron concentration in a conductor is 6.6 × 10²¹ m^-3. The electron mobility is 135 m² V^-1 s^-1. Find the conductivity of the conductor.

The resistivity of copper is 1.6 × 10^-8 m S^-1. Find the electric field in a copper wire of area of cross-section 4 mm² and the current flowing is 2.5 A