﻿ Medical Entrance Exam Question and Answers | Electric Charges and Fields - Zigya

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# Electric Charges and Fields

#### Multiple Choice Questions

61.

Two small charged spheres A and B have charges 10 C and 40 C respectively and are held at a separation of 90 cm from each other. At what distance from A, the electric intensity would be zero?

• 22.5 cm

• 18 cm

• 36 cm

• 30 cm

62.

A charged particle moves in an electric field from A to B, then from B to A :

• If WAB > WBA, then the field is conservative

• If WAB + WBA = 0, then the field is conservative

• If WAB + WBA > 0, then the field is conservative

• If WAB = WBA, then the field is conservative

63.

What is the angle between the electric dipole moment and the electric field strength due to it on the equatorial line?

• 90°

• 180°

• None of these

64.

Two spheres of radii R1 and R2 respectively are charged and joined by a wire. The ratio of the electric field of spheres is :

• $\frac{{\mathrm{R}}_{2}^{2}}{{\mathrm{R}}_{1}^{2}}$

• $\frac{{\mathrm{R}}_{1}^{2}}{{\mathrm{R}}_{2}^{2}}$

• $\frac{{\mathrm{R}}_{2}}{{\mathrm{R}}_{1}}$

• $\frac{{\mathrm{R}}_{1}}{{\mathrm{R}}_{2}}$

65.

The figure shows three points A, B and C in a region of a uniform electric field $\stackrel{\to }{\mathrm{E}}$. The line AB is perpendicular and BC is parallel to the field lines. Then which of the following holds good?

• VA = VB = VC

• VA = VB > VC

• VA = VB < VC

• VA > VB = VC

66.

The unit of permittivity (${\mathrm{\epsilon }}_{0}$) of space is

• newton-metre/ coulomb2

• coulomb / newton-metre

• coulomb / newton-metre2

• coulomb/ newton-metre2

67.

Two charges each of equal magnitude 3.2 x 10-19 coulomb but of opposite sign form an electric dipole. The distance between the two charges is 2.4 $\stackrel{\circ }{\mathrm{A}}$. If the dipole is placed in an electric field of 5 x 105 volt/metre, then in equilibrium its potential energy will be

• 3 × 15-23 joule

• -3.84 × 10-23 joule

• -6 × 10-23 joule

• -2 × 10-26 joule

68.

1 newton/coulomb is equivalent to

• 1 C/V

• 1 J

• 1 V/M

• 1 J/C

69.

An electron is moving with velocity v on a circular path of radius r in a transverse electric field B. The specific charge (e/m) of the electron is

• Bvr

• $\frac{\mathrm{\nu }}{\mathrm{Br}}$

• Bvr2

• $\frac{\mathrm{B}}{\mathrm{r\nu }}$

70.

Number of extra electrons in a body of charge -80$\mathrm{\mu }$C, is

• 80 × 1015

• 80 × 10−15

• 5 × 1014

• 1.28 × 10−17