MCQs of Electric Charges and Electric Fields

Electric Charges and Electric Fields MCQs

MCQs of Electric Charges and Electric Fields

Showing 81 to 90 out of 141 Questions

81.

The electric field at the centroid of an equilateral triangle carrying an equal charge q at each of the vertices is _____ .

(a)	$\frac{3 k q}{r^{2}}$
(b)	$\frac{k q}{\sqrt{2} r^{2}}$
(c)	$\frac{\sqrt{2} k q}{r^{2}}$
(d)	zero

82.

The relation between the intensity of the electric field of an electric dipole at a distance 'r' from its centre on its axis and the distance 'r' is _____ . (where r >> 2a)

(a)	$E \propto \frac{1}{r^{3}}$
(b)	$E \propto \frac{1}{r^{4}}$
(c)	$E \propto \frac{1}{r^{2}}$
(d)	$E \propto \frac{1}{r}$

83.

There exists an electric field of N/C along the y-directions. The flux passing through the square of 1 m placed in xy plane inside the electric field is _____ .

(a)	1.0 N m² C
(b)	10.0 N m² C
(c)	2.0 N m² C
(d)	zero

84.

The Gaussian surface for calculating the electric field due to a charge distribution is _____ .

(a)	any surface near the charge distribution
(b)	always a spherical surface
(c)	a symmetrical closed surface containing the charge distribution at every point of which electric field has a single fixed value
(d)	None of the above

85.

Charge q₂ of mass m revolves around a stationary charge q₁ in a circular orbit of radius r. The orbital periodic charge of q₂ would be _____ .

(a)	${[\frac{4 π^{2} m r^{3}}{k q_{1} q_{2}}]}^{\frac{1}{2}}$
(b)	${[\frac{k q_{1} q_{2}}{4 π^{2} m r^{3}}]}^{\frac{1}{2}}$
(c)	${[\frac{4 π^{2} m r^{4}}{k q_{1} q_{2}}]}^{\frac{1}{2}}$
(d)	${[\frac{4 π^{2} m r^{2}}{k q_{1} q_{2}}]}^{\frac{1}{2}}$

86.

If two small balls, each carrying charge +q, are connected by a non-conducting string of length 2a, then what is the tension in the string ?

(a)	$\frac{q^{2}}{4 π ε_{0} a^{2}}$
(b)	$\frac{q^{2}}{8 π ε_{0} a^{2}}$
(c)	$\frac{q^{2}}{16 π ε_{0} a^{2}}$
(d)	$\frac{q^{2}}{32 π ε_{0} a^{2}}$

87.

If F is the force between two points charges submerged in a medium of dielectric constant K, then on with drawing the medium, the force between the charges becomes _____ .

(a)	$\frac{F}{K}$
(b)	$\frac{F}{\sqrt{K}}$
(c)	FK
(d)	$F \sqrt{K}$

88.

A charge 10^-9 C is located at the origin of Cartesian co-ordinate system and another charge Q at (2, 0, 0) m. If the Y-component of the electric field at (3, 1, 1) m is zero, then the value of charge Q is _____ C.

(a)	-0.43 ×10^-9
(b)	-0.1424 ×10^-9
(c)	-4.3 ×10^-9
(d)	None of the above

89.

Dimensional formulas for electric field is _____ .

(a)	$M^{1} L^{2} T^{- 3} A^{- 2}$
(b)	$M^{1} L^{1} T^{- 3} A^{- 1}$
(c)	$M^{1} L^{2} T^{- 3} A^{- 1}$
(d)	$M^{0} L^{0} T^{0} A^{0}$

90.

A particle having mass m and charge q is at rest. ON applying a uniform electric field E on it , it starts moving. What is the kinetic energy, when it travels a distance x in the direction of force ?

(a)	qE²x
(b)	qEx²
(c)	q²Ex
(d)	qEx

Showing 81 to 90 out of 141 Questions