Assertion : If the current in a solenoid is r | vedclass

Name: Exam Paper Generator | JEE NEET Paper Generator | Vedclass
Brand: Vedclass
Rating: 5 (35 reviews)

Question

(C) The magnetic field $B$ inside a solenoid is given by $B = \mu_0 n I$,where $I$ is the current.The magnetic field energy density $u$ is given by $u

Vedclass · Accepted Answer

If Assertion is correct but Reason is incorrect.

Vedclass · Answer

(C) The magnetic field $B$ inside a solenoid is given by $B = \mu_0 n I$,where $I$ is the current.The magnetic field energy density $u$ is given by $u = \frac{B^2}{2\mu_0} = \frac{(\mu_0 n I)^2}{2\mu_0} = \frac{1}{2} \mu_0 n^2 I^2$.Since the energy density $u$ is proportional to $I^2$,reversing the direction of the current (i.e.,changing $I$ to $-I$) does not change the value of $I^2$.Therefore,the magnetic field energy stored in the solenoid remains constant.Since the Assertion claims the energy decreases,the Assertion is incorrect.The Reason states that energy density is proportional to the square of the current,which is correct.Thus,the Assertion is incorrect and the Reason is correct.

Assertion : If the current in a solenoid is reversed in direction while keeping the same magnitude,the magnetic field energy stored in the solenoid decreases.
Reason : Magnetic field energy density is proportional to the square of the current.

Similar Questions

$A$ closely wound solenoid of $80 \,cm$ long has $5$ layers of windings of $400$ turns each. The diameter of the solenoid is $1.8 \,cm$. If the current carried is $8 \,A$, then the magnitude of the magnetic field inside the solenoid near its centre is approximately

The magnetic induction along the axis of a toroidal solenoid is independent of

The ratio of the magnetic field inside a solenoid at an axial point well inside and at an axial end point is

Assertion: The magnetic field produced by a current-carrying solenoid is independent of its length and cross-sectional area.
Reason: The magnetic field inside the solenoid is uniform.

In a toroid,the magnetic field on the axis is to be calculated given the radius $r = 0.5 \, cm$,current $I = 1.5 \, A$,number of turns $N = 250$,and relative permeability $\mu_r = 700$. Find the magnetic field $B$ (in Tesla). (in $.5$)

Vedclass Test Series

Exam Paper Generator

Online Exam Module

Assertion : If the current in a solenoid is reversed in direction while keeping the same magnitude,the magnetic field energy stored in the solenoid decreases.Reason : Magnetic field energy density is proportional to the square of the current.