Current Electri...

Consider a current carrying wire (current I) in the shape of a circle.

A resistance R is to be measured using a meter bridge, student chooses the standard resistance S to be 100\(\Omega\). He finds the null point at \(l _1\) = 2.9 cm. He is told to attempt to improve the accuracy. Which of the following is a useful way?

Two cells of emfs approximately 5 V and 10 V are to be accurately compared using a potentiometer of length 400 cm

A metal rod of length 10 cm and a rectangular cross-section of 1cm x \(1 \over2\)cm is connected to a battery across opposite faces. The resistance will be

Which of the following characteristics of electrons determines the current in a conductor?

Kirchhoff’s junction rule is a reflection of

(a) conservation of current density vector

(b) conservation of charge

(c) the fact that the momentum with which a charged particle approaches a junction is unchanged (as a vector) as the charged particle leaves the junction

(d) the fact that there is no accumulation of charges at a junction

Temperature dependence of resistivity \(\rho\)(T) of semiconductors, insulators and metals is significantly based on the following factors

(a) number of charge carriers can change with temperature T

(b) time interval between two successive collisions can depend on T

(c) length of material can be a function of T

(d) mass of carriers is a function of T