MCQs of Moving Charges & Magnetism

Moving Charges & Magnetism MCQs

MCQs of Moving Charges & Magnetism

Showing 111 to 120 out of 123 Questions

111.

A long straight wire carrying current of 30 A is placed in an external uniform magnetic field of induction 4×10^-4T. The magnetic field is acting parallel to the direction of current. What is the magnitude of the resultant magnetic induction in tesla at a point 2.0 cm away from the wire ?

(a)	10^-4
(b)	3×10^-4
(c)	5×10^-4
(d)	6×10^-4

112.

Two particles X and Y having equal charge, after being accelerated through the same potential difference, enter a region of uniform magnetic field and describe circular paths of radius R₁ and R₂ respectively. What is the ratio of mass of X to that of Y ?

(a)	${(\frac{R_{1}}{R_{2}})}^{\frac{1}{2}}$
(b)	$\frac{R_{2}}{R_{1}}$
(c)	${(\frac{R_{1}}{R_{2}})}^{2}$
(d)	$\frac{R_{1}}{R_{2}}$

113.

A proton is moving perpendicularly to a uniform magnetic field of 2.5 tesla with 2 MeV kinetic energy. The force on the proton is ____ .

(a)	3×10^-10N
(b)	8×10^-11N
(c)	3×10^-11N
(d)	8×10^-12N

114.

A proton and an α-particle enter a uniform magnetic field perpendicularly with the same speed. If proton takes 25 μs to make 5 revolution, then what is the periodic time for the α-particle ?

(a)	50 μ sec
(b)	25 μ sec
(c)	10 μ sec
(d)	5 μ sec

115.

A proton (mass 1.67 × 10^-27 kg and charge = 1.6×10^-19C) enters perpendicularly to a magnetic field of intensity 2 weber/m² with a velocity 3.4 × 10⁷ m/s. What is the acceleration of the proton ?

(a)	6.5×10¹⁵ m/s²
(b)	6.5×10¹³ m/s²
(c)	6.5×10¹¹ m/s²
(d)	6.5×10⁹ m/s²

116.

If a particle of charge 10^-12 columb moving along the

\hat{x}

-direction with a velocity 10⁵ m/s experiences a force of 10^-10 newton in

\hat{y}

-direction due to magnetic field. What is the minimum magnetic field

\vec{B}

(a)	625 × 10³ tesla, in negative z-direction
(b)	10^-15 tesla, in negative z-direction
(c)	128 × 10^-13 tesla, in negative z-direction
(d)	10^-3 tesla, in negative z-direction

117.

A charged particle of mass m and charge q describes circular motion of radius r in a uniform magnetic field of strength B. What is the frequency of revolution ?

(a)	$\frac{B q}{2 π m}$
(b)	$\frac{B q}{2 π r m}$
(c)	$\frac{2 π m}{B q}$
(d)	$\frac{B m}{2 π q}$

118.

magnetic field at two points on the axis of a circular coil at a distance of 0.05 m and 0.2 m from the centre are in the ratio of 8:1. The radius of the coil is _____ .

(a)	1.0 m
(b)	0.1 m
(c)	0.15 m
(d)	0.2 m

119.

Wire in the form of a square of side 'a' carries a current I. Then the magnetic induction at the centre of the centre of the square wire is _____. (Magnetic permeability of free space μ₀)

(a)	$\frac{μ_{0} I}{2 π a}$
(b)	$\frac{μ_{0} I \sqrt{2}}{2 a}$
(c)	$\frac{2 \sqrt{2} μ_{0} I}{π a}$
(d)	$\frac{μ_{0} I}{\sqrt{2} π a}$

120.

two similar coils are kept mutually perpendicular such that their centre coincide. At the centre, find the ratio of the magnetic field due to one coil and the resultant magnetic field by both coils, if the same current is flown.

(a)	$1 : \sqrt{2}$
(b)	1:2
(c)	2:1
(d)	$\sqrt{3} : 1$

Showing 111 to 120 out of 123 Questions