Day 297: JEE Mains Physics

Moving Charges and Magnetism. Asked once: 30 Jan 2023 (same type asked 4 times) See all 4 of this type

17

A massless square loop, of wire of resistance $10\Omega$, supporting a mass of $1\text{ }g$, hangs vertically with one of its sides in a uniform magnetic field of $10^{3}G$, directed outwards in the shaded region. A dc voltage $V$ is applied to the loop. For what value of $V$, the magnetic force will exactly balance the weight of the supporting mass of $1\text{ }g$ ? (If sides of the loop $= 10\text{ }cm,g = 10{\text{ }ms}^{- 2}$ )

1. A.
   $\frac{1}{10}\text{ }V$
2. B.
   $100\text{ }V$
3. C.
   $10\text{ }V$
4. D.
   $1\text{ }V$

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Electrostatics. Asked once: 10 Apr 2023 (same type asked 4 times) See all 4 of this type

120

An electron revolves around an infinite cylindrical wire having uniform linear charge density $2 \times10^{- 8}Cm^{- 1}$ in circular path under the influence of attractive electrostatic field as shown in the figure. The velocity of electron with which it is revolving is____ $\times10^{6}{\text{ }ms}^{- 1}$. Given mass of electron $= 9 \times10^{- 31}\text{ }kg$.

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Kinetic Theory. Asked once: 29 Jan 2024 (same type asked 4 times) See all 4 of this type

Wave Optics. Asked once: 29 Jul 2022 (same type asked 4 times) See all 4 of this type

Electromagnetic Induction. Asked once: 11 Apr 2023 (same type asked 4 times) See all 4 of this type

28

The magnetic field $B$ crossing normally a square metallic plate of area $4{\text{ }m}^{2}$ is changing with time as shown in figure. The magnitude of induced emf in the plate during $t = 2\text{ }s$ to $t = 4\text{ }s$, is ___$mV$

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