MHT CET 2025 25th April Morning Shift | Moving Charges and Magnetism Question 9 | Physics

A long straight wire of radius ' $r$ ' carries a steady current ' $I$ '. The current is uniformly distributed over its cross-section. The ratio $\left(\frac{B}{B_1}\right)$ of the magnetic field ' B ' and ' $\mathrm{B}_1$ ' at radial distances ' $\frac{r}{2}$ ' and ' $3 r$ respectively, from the axis of the wire is

$\frac{1}{2}$

$\frac{3}{2}$

$\frac{5}{2}$

$\frac{1}{2}$

MHT CET 2025 23rd April Evening Shift

MCQ (Single Correct Answer)

-0

In hydrogen atom, an electron of charge 'e' revolves in an orbit of radius ' $r$ ' with speed ' $v$ '. The magnetic moment associated with electron is

$\frac{\mathrm{evr}}{3}$

$\frac{\mathrm{evr}}{2}$

evr

$\sqrt{2} \mathrm{evr}$

MHT CET 2025 23rd April Evening Shift

MCQ (Single Correct Answer)

-0

Two current carrying identical coils are kept as shown in figure. The magnetic field at centre ' O ' is ( N and R represent the number of turns and radius of each coil respectively, $\mu_0=$ permeability of free space)

MHT CET 2025 23rd April Evening Shift Physics - Moving Charges and Magnetism Question 4 English

$\frac{\mu_0 \mathrm{NI}}{2 R}$

$\frac{\mu_0 N I}{\sqrt{2} R}$

$\frac{\mu_0 N I}{2 \sqrt{2} R}$

$\frac{\mu_0 \mathrm{~N}}{2}$

MHT CET 2025 23rd April Evening Shift

MCQ (Single Correct Answer)

-0

The relation between magnetic moment $(\mathrm{M})$ of a current carrying circular coil and length (L) of the wire used is

$\mathrm{M} \propto \mathrm{L}$

$\mathrm{M} \propto \frac{1}{\mathrm{~L}}$

$\mathrm{M} \propto \mathrm{L}^2$

$\mathrm{M} \propto \frac{1}{\mathrm{~L}^2}$

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