JEE PHYSICS MCQ: MAGNETIC EFFECT OF CURRENT

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At the mid-point along the length of a long solenoid, the magnetic field is equal to

X

. If the length of the solenoid is doubled and the current is reduced to half the field at the new mid-point will be nearest to

View answer and explanation

Correct option: B

\frac{X}{2}

Option B (

\frac{X}{2}

) is correct because the magnetic field inside a long solenoid is proportional to the number of turns per unit length and the current. Doubling the length halves the turns per unit length, and halving the current halves the magnetic field.

More Questions from MAGNETIC EFFECT OF CURRENT

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A needle made of bismuth is suspended freely in a magnetic field. The angle which the needle makes with the magnetic field is: Assertion: If a charged particles is moving in perpendicular uniform magnetic field, its kinetic energy does not change
Reason: Velocity of charge particle is not changing in magnetic field. Pick out the wrong statement : A steady current is flowing in a circular coil of radius

R

, made up of a thin conducting wire. The magnetic field at the center of the loop is

B_L

. Now, a circular loop of radius

R/n

is made from the same wire without changing its length, by unfolding and refolding the loop, and the same current is passed through it. If new magnetic field at the center of the coil is

B_C

, then the ratio

B_L / B_C

is Lorentz force can be calculated by using the formula Two particles

X

and

Y

having equal charges, after being accelerated through the same potential difference, enter a region of uniform magnetic field and describe circular path of radius

R_1

and

R_2

respectively. The ratio of mass of

{X}

to that of

{Y}

is :