MCQ
Current density of a conductor is
- AIs always zero
- Bthe net charge flowing through the area
- Cmeasure of the flow of electric charge in amperes per unit area of cross-section
- Dthe net charge flowing through the area per unit time
✓
Answer
(c) : measure of the flow of electric charge in amperes per unit area of cross-section
Explanation: Current density $J =\frac{I}{A}$
In electromagnetism, current density is the electric current per unit area of cross section. Or It is the measure of the flow of electric charge in amperes per unit area of cross-section .It is a vector and has a direction along the area vector.
Explanation: Current density $J =\frac{I}{A}$
In electromagnetism, current density is the electric current per unit area of cross section. Or It is the measure of the flow of electric charge in amperes per unit area of cross-section .It is a vector and has a direction along the area vector.
Need a full question paper?
Generate a complete, print-ready paper with questions like this in minutes — across 16+ boards, with answer keys.
Explore more
Similar questions
On going from north pole to equator, the value of angle of dip :
The de-Broglie wavelength of an electron in the first Bohr orbit is
|
(a) Equal to one fourth the circumference of the first orbit |
|
(b) Equal to half the circumference of the first orbit |
|
(c) Equal to twice the circumference of the first orbit |
|
(d) Equal to the circumference of the first orbit |
A closely wound flat circular coil of 25 turns of wire has diameter of 10 cm and carries a current of 4 ampere. Determine the flux density at the centre of a coil
|
(a) 1.679 |
(b) 2.028 |
|
(c) 1.257 |
(d) 1.512 |
With the rise in temperature, the dielectric constant K of a liquid
|
(a) Increases |
(b) Decreases |
|
(c) Remains unchanged |
(d) Charges erratically |
Which of the following materials has a negative temperature coefficient of resistance?
The clear sky appears blue because:
The bottom of a container filled with liquid appear slightly raised because of
|
(a) Refraction |
(b) Interference |
(c) Diffraction |
(d) Reflection |
A uniform wire of resistance $50\Omega$ is cut into 5 equal parts. These parts are now connected in parallel. The equivalent resistance of the combination is:
→- $2\Omega$
- $10\Omega$
- $250\Omega$
- $6250\Omega$
Assertion : Short wave bands are used for transmission of ratio waves to a large distance
Reason : Short waves are reflected by ionosphere
|
(a) If both assertion and reason are true and the reason is the correct explanation of the assertion. |
|
(b) If both assertion and reason are true but reason is not the correct explanation of the assertion. |
|
(c) If assertion is true but reason is false. |
| (d) If assertion is false but reason is true. |
A small sphere carrying a charge ‘q’ is hanging in between two parallel plates by a string of length L. Time period of pendulum is 
. When parallel plates are charged, the time period changes to T . The ratio 
is equal to
|
(a) |
(b) |
(c) |
(d) None of these |
