EASY

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The order of magnitude of minimum electrostatic force between two charge particles at a separation of 1m is

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Important Questions on Electric Charges and Fields

EASY

Physics>Electricity and Magnetism>Electric Charges and Fields>Coulomb's Laws

Suppose the charge of a proton and an electron differ slightly. One of them is

e

, the other is

(e + Δ e)

. If the net electrostatic force and gravitational force between two hydrogen atoms placed at a distance

d

(much greater than atomic size) apart is zero, then

Δ e

is of the order of [Given mass of hydrogen

m_{h} = 1.67 \times 10^{- 27} kg

]

MEDIUM

Physics>Electricity and Magnetism>Electric Charges and Fields>Coulomb's Laws

Directions: Each of the following sentences in this section has a blank space and four words or group of words given after the sentence. Select the word or group of words you consider most appropriate for the blank space and indicate your response on the Answer Sheet accordingly.

Every rash driver becomes a ____ killer.

MEDIUM

Physics>Electricity and Magnetism>Electric Charges and Fields>Coulomb's Laws

The radius of a nucleus is given by

r_{0} A^{1 / 3}

where

r_{0} = 1.3 \times 10^{- 15} m

and

A

is the mass number of the nucleus, the Lead nucleus has

A = 206

, the electrostatic force between two protons in this nucleus is approximately

EASY

Physics>Electricity and Magnetism>Electric Charges and Fields>Coulomb's Laws

Two point charges A and B, having charges

+ Q

and

- Q

respectively, are placed at certain distance apart and force acting between them is

F

. If

25 %

charge of

A

is transferred to

B

, then the force between the charges becomes

MEDIUM

Physics>Electricity and Magnetism>Electric Charges and Fields>Coulomb's Laws

A point charge

+ Q

is held at rest at a point

P .

Another point charge

- q

, whose mass is

m

, moves at a constant speed

v

in a circular orbit of radius

R_{1}

around

P

. The work required to increase the radius of revolution of

- q

from

R_{1}

, to another orbit

R_{2}

(R_{2} > R_{1})

(where K = \frac{1}{4 π ε_{0}})

EASY

Physics>Electricity and Magnetism>Electric Charges and Fields>Coulomb's Laws

Two charges of equal magnitudes and at a distance $r$ exert a force $F$ on each other. If the charges are halved and distance between them is doubled, then the new force acting on each charge is

MEDIUM

Physics>Electricity and Magnetism>Electric Charges and Fields>Coulomb's Laws

Four identical pendulums are made by attaching a small ball of mass

100 g

on a

20 cm

long thread and suspended from the same point. Now each ball is given charge

q

so that balls move away from each other with each thread making an angle of

45^{o}

from the vertical. The value of

q

is close to

(\frac{1}{4 {πε}_{0}} = 9 \times 10^{9}, S . I . u n i t s)

EASY

Physics>Electricity and Magnetism>Electric Charges and Fields>Coulomb's Laws

The acceleration of an electron due to the mutual attraction between the electron and a proton when they are

1.6 Å

apart is,

(m_{e} ≃ 9 \times 10^{- 31} kg, e = 1.6 \times 10^{- 19} C)

(Take

\frac{1}{4 π ε_{0}} = 9 \times 10^{9} N m^{2} C^{- 2}

)

EASY

Physics>Electricity and Magnetism>Electric Charges and Fields>Coulomb's Laws

Two sentences are given below and you are required to find the correct sentence which combines both the sentences.

Which is the correct combination of the given two sentences?

He is too tired. He could not stand.

EASY

Physics>Electricity and Magnetism>Electric Charges and Fields>Coulomb's Laws

The dimensions of

ε_{0}

(permittivity in free space) is

MEDIUM

Physics>Electricity and Magnetism>Electric Charges and Fields>Coulomb's Laws

In the following sentence, a blank space with four options is given. Select whichever preposition or determiner you consider the most appropriate for the blank space.

These are the good rules to live _____.

HARD

Physics>Electricity and Magnetism>Electric Charges and Fields>Coulomb's Laws

Two identical charged spheres suspended from a common point by two massless strings of lengths

l

, are initially at a distance

d (d ≪ l)

apart because of their mutual repulsion. The charges begin to leak from both the spheres at a constant rate. As a result, the spheres approach each other with a velocity

υ

. Then

υ

varies as a function of the distance

x

between the spheres, as

HARD

Physics>Electricity and Magnetism>Electric Charges and Fields>Coulomb's Laws

A certain charge

2 Q

is divided at first into two parts

q_{1}

and

q_{2}

. Later the charges are placed at a certain distance. If the force of interaction between two charges is maximum then

\frac{Q}{q_{1}} =

HARD

Physics>Electricity and Magnetism>Electric Charges and Fields>Coulomb's Laws

Two small metal balls of different masses

m_{1}

and

m_{2}

are connected by strings of equal length to a fixed point. When the balls are given equal charges, the angles that the two strings make with the vertical are

30 °

and

60 °

, respectively. The ratio

\frac{m_{1}}{m_{2}}

is close to,

HARD

Physics>Electricity and Magnetism>Electric Charges and Fields>Coulomb's Laws

Two identical non-conducting solid spheres of same mass and charge are suspended in air from a common point by two non-conducting, massless strings of same length. At equilibrium, the angle between the strings is

α

. The spheres are now immersed in a dielectric liquid of density

800 kg m^{- 3}

and dielectric constant

21

. If the angle between the strings remains the same after the immersion, then

EASY

Physics>Electricity and Magnetism>Electric Charges and Fields>Coulomb's Laws

Two small metal spheres

A

and

B

charged positively are separated by

2 m

in air. The force on a charge of

+ 1 C

placed on the line joining the centres of the spheres and at a distance of

0.5 m

from

A

is found to be zero. The ratio

q_{A} : q_{B}

of charges on

A

and

B

EASY

Physics>Electricity and Magnetism>Electric Charges and Fields>Coulomb's Laws

Two electrons are moving with equal speed of

5 \times 10^{5} m s^{- 1}

parallel to each other. The ratio of the electrostatic to the magnetic force between them is

HARD

Physics>Electricity and Magnetism>Electric Charges and Fields>Coulomb's Laws

Two positively charged spheres of masses

m_{1} and m_{2}

are suspended from a common point at the ceiling by identical insulating massless strings of length

l

. Charges on the two spheres are

q_{1} and q_{2}

, respectively. At equilibrium, both strings make the same angle

θ

with the vertical. Then

HARD

Physics>Electricity and Magnetism>Electric Charges and Fields>Coulomb's Laws

Two charges, each equal to

q

, are kept at

x = - a

and

x = a

on the x-axis. A particle of mass

m

and charge

q_{0} = - \frac{q}{2}

is placed at the origin. If charge

q_{0}

is given a small displacement

(y ≪ a)

along the y-axis, the net force acting on the particle is proportional to :

MEDIUM

Physics>Electricity and Magnetism>Electric Charges and Fields>Coulomb's Laws

Three charges

+ Q, q, + Q

are placed respectively, at distance,

0, d / 2

and

d

from the origin, on the

x

-axis. If the net force experienced by

+ Q,

placed at

x = 0,

is zero, then value of

q

is:

The order of magnitude of minimum electrostatic force between two charge particles at a separation of 1m is

Important Questions on Electric Charges and Fields

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