The electric fields of two plane electromagnetic plane waves in vacuum are given by E 1 → = E 0 cos ω t - k x j ^ and E 2 → = E 0 cos ω t - k y k ^ , at t = 0 , a particle of charge q is at origin with a velocity v → = 08 c j ^ ( c is the speed of light in vaccum). The instantaneous force experienced by the particle is:

E 0 q 0 .8 i ^ + j ^ + 0 .2 k ^

E 0 q 0 .8 i ^ - j ^ + 0 .4 k ^

E 0 q 0 .4 i ^ - 3 j ^ + 0 .8 k ^

Given below are two statements : One is labelled as Assertion A and the other is labelled as Reason R. Assertion A : For measuring the potential difference across a resistance of 600 Ω , the voltmeter with resistance 1000 Ω will be preferred over voltmeter with resistance 4000 Ω . Reason R : Voltmeter with higher resistance will draw smaller current than voltmeter with lower resistance. In the light of the above statements, choose the most appropriate answer from the options given below

A is not correct but R is correct

Both A and R are correct and R is the correct explanation of A

Both A and R are correct but R is not the correct explanation of A

A is correct but R is not correct

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A long, straight Wire of radius a carries a current distributed uniformly over its cross-section. The ratio of the magnetic fields due to the wire at distance $\frac{a}{3}$ and $2 a$ , respectively from the axis of the wire is:

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Important Questions on Magnetic Effects of Current and Magnetism

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JEE Main

IMPORTANT

EMBIBE CHAPTER WISE PREVIOUS YEAR PAPERS FOR PHYSICS>Chapter 15 - Magnetic Effects of Current and Magnetism>JEE Main - 9th January 2020 Shift 1>Q 63

The electric fields of two plane electromagnetic plane waves in vacuum are given by

\vec{E_{1}} = E_{0} \cos (ω t - k x) \hat{j}

and

\vec{E_{2}} = E_{0} \cos (ω t - k y) \hat{k}

, at

t = 0,

a particle of charge

q

is at origin with a velocity

\vec{v} = 08 c \hat{j}

(

c

is the speed of light in vaccum). The instantaneous force experienced by the particle is:

HARD

JEE Main

IMPORTANT

EMBIBE CHAPTER WISE PREVIOUS YEAR PAPERS FOR PHYSICS>Chapter 15 - Magnetic Effects of Current and Magnetism>JEE Main - 9th January 2020 Shift 2>Q 64

A small circular loop of conducting wire has radius a and carries current

I .

It is placed in a uniform magnetic field

B

perpendicular to its plane such that when rotated slightly about its diameter and released, it starts performing simple harmonic motion of time period

T .

The mass of the loop is

m

then:

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EMBIBE CHAPTER WISE PREVIOUS YEAR PAPERS FOR PHYSICS>Chapter 15 - Magnetic Effects of Current and Magnetism>JEE Main - 9th January 2020 Shift 2>Q 65

An electron gun is placed inside a long solenoid of radius

R

on its axis. The solenoid has

n

turns/length and carries a current

I .

The electron gun shoots an electron along the radius of the solenoid with speed

v .

If the electron does not hit the surface of the solenoid, maximum possible value of

v

is (all symbols have their standard meaning):

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JEE Main

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EMBIBE CHAPTER WISE PREVIOUS YEAR PAPERS FOR PHYSICS>Chapter 15 - Magnetic Effects of Current and Magnetism>JEE Main - 9th April 2019 Shift 1>Q 66

A rigid square loop of side $‘ a ’$ and carrying current $I_{2}$ is lying on a horizontal surface near a long current $I_{1}$ carrying wire in the same plane as shown in figure. The net force on the loop due to the wire will be:
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EMBIBE CHAPTER WISE PREVIOUS YEAR PAPERS FOR PHYSICS>Chapter 15 - Magnetic Effects of Current and Magnetism>JEE Main - 9th April 2019 Shift 1>Q 67

A rectangular coil (Dimension

5 c m \times 2.5 c m

) with

100

turns, carrying a current of

3 A

in the clock-wise direction, is kept centered at the origin and in the

X - Z

plane. A magnetic field of

1 T

is applied along

X - a x i s

. If the coil is tilted through

45 °

about

Z - a x i s

, then the torque on the coil is:

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JEE Main

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EMBIBE CHAPTER WISE PREVIOUS YEAR PAPERS FOR PHYSICS>Chapter 15 - Magnetic Effects of Current and Magnetism>JEE Main - 9th April 2019 Shift 1>Q 68

A moving coil galvanometer has resistance

50 Ω

and it indicates full deflection at

4 m A

current. A voltmeter is made using this galvanometer and a

5 k Ω

resistance. The maximum voltage, that can be measured using this voltmeter, will be close to:

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EMBIBE CHAPTER WISE PREVIOUS YEAR PAPERS FOR PHYSICS>Chapter 15 - Magnetic Effects of Current and Magnetism>JEE Main - 9th January 2019 Shift 1>Q 69

A current loop, having two circular arcs joined by two radial lines is shown in the figure. It carries a current of

10 A .

The magnetic field at point

O

will be close to:
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JEE Main

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EMBIBE CHAPTER WISE PREVIOUS YEAR PAPERS FOR PHYSICS>Chapter 15 - Magnetic Effects of Current and Magnetism>JEE Main - 9th January 2019 Shift 1>Q 70

A bar magnet is demagnetized by inserting it inside a solenoid of length

0.2 m, 100

turns, and carrying a current of

5.2 A .

The coercivity of the bar magnet is:

A long, straight Wire of radius a carries a current distributed uniformly over its cross-section. The ratio of the magnetic fields due to the wire at distance a3 and 2a , respectively from the axis of the wire is:

Important Questions on Magnetic Effects of Current and Magnetism

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A long, straight Wire of radius a carries a current distributed uniformly over its cross-section. The ratio of the magnetic fields due to the wire at distance $\frac{a}{3}$ and $2 a$ , respectively from the axis of the wire is: