Why is the coil wrapped on a conducting frame?

Why is the mode of conduction of electrical impulse along the myelinated neurons advantageous to a non-myelinated neuron? What is this type of conduction called?

Why is the coil of a dead-beat galvanometer wound on a metal frame ?

Why is the coil of a dead beat galvanometer wound on a metal frame?

Why is the core of moving coil galvanometer laminated?

Why does the conductivity of a solution decrease with dilution?

Answer the following questions: Why is choke coil needed in the use of fluorescent tubes with ac mains? Why can we not use an ordinary resistor instead of the choke coil?

Prior to a sports event blood & urine sample of sports persons are collected for drug tests. Why is there a need to conduct such tests.

Why should gases be insulators at ordinary pressure and start conducting at very low pressure?