Magnetic Effects of Current & Magnetism · JEE Advanced previous year questions

1. A.(A)
2. B.(B)
3. C.(C)
4. D.(D)

A cube of unit volume contains $35\times 10^7$ photons of frequency $10^{15}$ Hz. If the energy of all the photons is viewed as the average energy being contained in the electromagnetic waves within the same volume, then the amplitude of the magnetic field is $\alpha \times 10^{-9}$ T. Taking permeability of free space ${\mu }_0=4\pi \times 10^{-7}$ Tm/A, Planck’s constant $h=6\times 10^{-34}$ Js and $\pi =\frac{22}{7}$, the value of $\alpha$ is ____

An infinitely long wire, located on the $z$-axis, carries a current $I$ along the $+z$-direction and produces the magnetic field $\vec{B}$. The magnitude of the line integral $\int \vec{B}\cdot d\vec{l}$ along a straight line from the point $(-\sqrt{3}a,a,0)$ to $(a,a,0)$ is given by [${\mu }_0$ is the magnetic permeability of free space.]

1. A.$7{\mu }_{0}I/24$
2. B.$7{\mu }_{0}I/12$
3. C.${\mu }_{0}I/8$
4. D.${\mu }_{0}I/6$

1. A.(A)
2. B.(B)
3. C.(C)
4. D.(D)

1. A.$\tan \theta =\pi rI{B}_0/(mg)$
2. B.$\tan \theta =2\pi rI{B}_0/(mg)$
3. C.$\tan \theta =\pi rI{B}_0/(2mg)$
4. D.$\tan \theta =mg/(\pi rI{B}_0)$

1. A.The value of $x$ for $H^{+}$ ion is 4 cm.
2. B.The value of $x$ for an ion with $A_{\mathrm{M}}=144$ is 48 cm.
3. C.For detecting ions with $1\le A_{\mathrm{M}}\le 196$, the minimum height $(x_1-x_0)$ of the detector is 55 cm.
4. D.The minimum width $w$ of the region of the magnetic field for detecting ions with $A_{\mathrm{M}}=196$ is 56 cm.