Electric Current & Conductivity

Which one of the following is the best conductor of electricity?

Assertion (A): Copper rods are generally preferred to iron rods for making lightning conductors. Reason (R) : Copper is better conductor of electricity than iron and is not easily oxidized under atmospheric conditions. Code :

Given below are two statements, in which one is labelled as Assertion (A) and the other as Reason (R). Assertion (A): A person travelling in a car with closed glass windows and doors is safe from the lightening strike. Reason (R): Actually a closed car behaves like a hollow conductor, so charges cannot enter inside the car. Select the correct answer using the code given below- Code :

At which temperature superconductivity can be of tremendous economic interest saving billions of rupees?

The highest temperature attained by a superconductor is :

The newly discovered high temperature super conductors are -

The resistance of a semiconductor on heating :

Which one of the following is an important component of a transistor?

The most commonly used material for making transistors is -

Which of the following are semiconductors? 1. Silicon 2. Quartz 3. Ceramics 4. Germanium Choose the correct answer from the following alternatives :

Which of the following is a semiconductor?