Question 1

What is the SI unit of electric current?

Accepted Answer

The SI unit of electric current is the Ampere (A), which is defined as one coulomb of charge passing through a cross-section of a conductor per second.

Question 2

Which of the following materials is an ohmic conductor?

Accepted Answer

Copper obeys Ohm's law strictly under constant physical conditions, making it an ohmic conductor, whereas diodes and transistors are non-ohmic.

Question 3

The drift velocity of electrons in a metallic conductor is of the order of:

Accepted Answer

Under normal electric fields in conductors, the drift velocity of electrons is typically of the order of 10^-4 m/s.

Question 4

What is the dimension of electrical resistance?

Accepted Answer

Resistance R = V/I = (W/q)/I = ML^2 T^-3 A^-2.

Question 5

Specific resistance (resistivity) of a wire depends upon:

Accepted Answer

Resistivity is an intrinsic property of the material and depends only on the nature of the material and temperature, not on its length or cross-sectional area.

Current Electricity — NCERT Class 12 Physics Important Questions & Revision Notes