MCQs of Moving Charges & Magnetism

Moving Charges & Magnetism MCQs

MCQs of Moving Charges & Magnetism

Showing 61 to 70 out of 123 Questions

61.

Two particles of masses M₁ and M₂ and having the equal electric charge are accelerated through equal potential difference and then move inside a uniform magnetic field, normal to it. If the radii of their circular paths are R₁ and R₂ respectively, find the ratio of their masses.

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

62.

The deflection in a moving-coil galvanometer falls from 50 divisions to 10 divisions, When a shunt of 12 Ω is connected with it, The resistance of galvanometer coil is _____ .

(a)	6Ω
(b)	48Ω
(c)	24Ω
(d)	12Ω

63.

A circular coil having N turns is made from a wire L meter long. If a current of I ampere is passed through this coil suspended in a uniform magnetic field of B tesla, find the maximum torque that can act on this coil.

(a)	$\frac{ILB}{2 πN}$
(b)	zero
(c)	$\frac{{IL}^{2} B}{4 πN}$
(d)	$\frac{{IL}^{2} B}{8 π^{2} N}$

64.

A proton and a deuteron having the same kinetic energies enter a region of uniform magnetic field perpendicularly. Deuteron's mass is twice that of proton. Calculate the ratio of the radii of their circular paths.

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

65.

An electron and a proton of equal linear momentum enter in the direction perpendicular to uniform magnetic field. If the radii of circular paths be r_e and r_p respectively, then

\frac{r_{e}}{r_{p}}

is equal to m_e=mass of electron. m_p=mass of proton

(a)	${(\frac{m_{e}}{m_{p}})}^{\frac{1}{2}}$
(b)	${(\frac{m_{p}}{m_{e}})}^{\frac{1}{2}}$
(c)	1
(d)	$\frac{m_{p}}{m_{e}}$

66.

A rectangular coil of 120 turns and an area of 10 x 10^-4 m² is suspended in a radial magnetic field of 45 x 10^-4 T. If a current of 0.2mA through the coil gives it a deflection of 36°, find the effective torsional constant for the spring system holding the coil.

(a)	17.2 x 10^-8
(b)	1.72 x 10^-8
(c)	12.7 x 10^-8
(d)	1.27 x 10^-8

67.

Two rings X and Y are placed in such a way that their axes are along the X and the Y axes respectively and their centres are at the origin. Both the rings X and Y have the same radii of 3.14 cm. If the current through X and Y rings are 0.6 A and 0.8 A respectively, find the value of the resultant magnetic field at the origin. (μ₀ = 4π x 10^-7 SI)

(a)	10^-5
(b)	2 x 10^-5
(c)	3 x 10^-5
(d)	4 x 10^-5

68.

Two parallel very long straight wires carrying currents of 20 A and 30 A respectively are at a separation of 3 m between them. If the currents are in the same direction, find the attractive force between them per unit length. (μ₀ = 4π x 10^-7 SI)

(a)	2 x 10^-5 $\frac{N}{m}$
(b)	3 x 10^-5 $\frac{N}{m}$
(c)	4 x 10^-5 $\frac{N}{m}$
(d)	10^-5 $\frac{N}{m}$

69.

A very long straight wire carries a current of 5 A. An electron moves with a velocity of 10⁶ ms^-1 remaining parallel to the wire at a distance of 10 cm from wire in a direction opposite to that of electric current. Find the force on this electron. (Here the mass of electron is taken as constant)

(e = -1.6 x 10^-19C, μ₀ = 4π x 10^-7 SI)

(a)	1.6 x 10^-19
(b)	1.6 x 10^-17
(c)	16 x 10^-19
(d)	16 x 10^-20

70.

An infinite straight current carrying conductor is bent in such a way that a circular loop is formed on it as shown in the figure. If the radius of the loop is R, the magnetic field at the centre of the loop is _____.

(a)	$\frac{μ_{0}}{4_{π}} . \frac{2 I}{r} (π + 1)$
(b)	$\frac{μ_{0}}{4_{π}} . \frac{2 I}{r} (π - 1)$
(c)	Zero
(d)	Infinite

Showing 61 to 70 out of 123 Questions