Question No. 1

which of the following methods can be used to charge a metal sphere positively without touching it . Select the best

Connect the positive terminal a battery and float the other end of the battery

Bring a negatively charged rod near the sphere and touch it to ground for a short while

Rub it with a piece of silk

Rub it with a piece of fur

Clear

If{\rm{1}}{0^{\rm{9}}}electrons move out of a body to another body every second, how much time is approximately required to get a total charge of 1 C on the other body?

200 years

120 years

180 years

220 years

Electric charge

is a property of protons only

is a property of particles such as atoms,ions,electrons etc that defines their behaviour in electrical fields.

is a property of neutrons onlz

is a property of electrons only

Clear

Electric charges are of

4 types

2 types

5 types

3 types

Conservation of charges in tribo electric charging

implies both are negatively charged

implies one is positively charged and the other is negatively charged.

implies half are positively charged and other half are neutral

implies both are positively charged

Clear

wo positive charges

always attract each other

repel each other

attract each other

attract each other at times and repel at other times

Clear

Charge is quantized means

charges can take on any continuous value

charges can take on discrete values that are multiples of charge on electron

charges can take on discrete values that are multiples of charge on neutron

charges can take on any discontinuous value

Clear

Ionization of a neutral atom is the

only gain of one or more neutrons

only gain of one or more electrons

only gain of one or more protons

gain or loss of one or more electrons

electrostatic force is

force exerted by an electron on a neutron

force exerted by one charge on another when the two are at rest in a given frame of reference

force exerted by one charge on another when the two are accelerating in a given frame of reference

force exerted by one charge on another when the two are moving in a given frame of reference

Clear

Conductors are materials

that allow only random movement of electrons

that allow movement of protons

that allow movement of electrons

that allow movement of neutrons

Clear

In charging by Induction

a metallic object is charged by bringing a charged object near it

a metallic object by touching touching with a charged object

a metallic object is charged by rubbing it with silk

a metallic object is charged by rubbing it with fur

Clear

For chargesq1andq2separated by a distance R the magnitude of the electrostatic force is given by

B .F=q1q240R

F=q1q240R3

F=q140R2

F=q1q240R2.

The unit of charge is

ampere

coulomb

ohm

volt

Electric field at a point is defined as

electric force experienced by a dipole at that point

electric force per unit charge experienced by a unit charge at that point

electric force experienced by a charge at that point

electric force experienced by two charges at that point

Clear

According to superposition of electric fields

The electric field of any combination of charges is the cross product of the individual fields.

The electric field of any combination of charges is the vector sum of the individual charges.

The electric field of any combination of charges is the vector sum of the fields caused by the individual charges.

The electric field of any combination of charges is the scalar sum of the fields caused by the individual charges.

Clear

Electric field lines can be said to be

lines of equal Electric field

graphical representation of electric fields.

drawing lines of electric fields

lines of equal Electric voltage

Clear

At any point on S on an electric field line

the perpendicular to the line is in the direction ofEat that point

the curvature is in the direction ofEat that point

the tangent to the line is in the direction ofEat that point

the binormal to the line is in the direction ofEat that point

Clear

An electric dipole is

a pair of electric charges of equal magnitude q but opposite sign, separated by a distance

a pair of electric charges of equal magnitude q but negative sign, separated by a distance d

a pair of electric charges of equal magnitude q but positive sign, separated by a distance d

a pair of electric charges of equal magnitude q separated by a distance d

Clear

The direction of an electric dipole

is perpendicular to line from positive to negative charge

is from negative to positive charge

is perpendicular to line from negative to positive charge

is from positive to negative charge

Clear

Electric flux

Is a measure of the electric power through a surface

Is a measure of the electric field potential through a surface

Is a measure of the area of electric field through a surface

Is a measure of the "flow" (in analogy with flow of fluids) of electric field through a surface.

ClearGauss's law states that

the total electric field flux coming out of a closed surface equals the net charge enclosed within the volume

the total electric field flux coming out of a closed surface equals the net charge enclosed within the volume divided by0

the total electric field flux coming out of an open surface equals the net charge enclosed within the volume divided by0

the total electric field flux coming out of a closed surface equals the charge enclosed within the volume divided by0

ClearAn electric dipole in an electric field experiences a torque {tex}\vec \tau {tex}

equal to the vector product of\vec E{tex} and{tex}\vec p

equal to the scalar product of\vec p{tex} and {tex}\vec E

equal to the scalar product of {tex}\vec E{tex} and{tex}\vec p{tex}

equal to the vector product of\vec p{tex} and {tex}\vec E

For a thin infinitely long straight wire of uniform linear charge densityat a distance R from the wire The magnitude ofE is

E=20R.

E=220R

B .E=40R

E=30R

For an Infinite thin plane sheet of uniform surface charge densitytexThemagnitudeoftexEis

A .E=20

E=220

E=203

E=0

For a thin spherical shell of uniform surface charge density, The magnitude ofEjust outside is

E=4R240r2

E=4R240r3

A .E=R240r2

E=4R240r2

Clear

An electric field can deflect

- rays

X rays

rays

Neutrons

Clear

Which one of the following graphs represents the variation of electric field strength E with distance r from the centre of a uniformly charged non conducting sphere?

Image B

Image C

Image D

Image A

Clear

A conducting sphere of radius 5 cm is charged to 15 {tex}\mu {tex} C. Another uncharged sphere of radius 10 cm is allowed to touch it for enough time. After the two are separated, the surface density of charge on the two spheres will be in the ratio

0.0840277777778

0.0423611111111

0.125694444444

0.0430555555556

Clear

A Gaussian sphere encloses an electric dipole within it. Total flux across the sphere is

dependent on position of the charge

double that due to single charge

half that due to a single charge

Zero

A cylinder of radius R and length L is placed in an uniform electric field E parallel to the cylinder axis. The total flux for the surface of the cylinder is given by

R2E

2R2E

R2+L2

C .0

When a negatively charged conductor is connected to earth,

Electrons flow from the conductor to the earth

Protons flow from the conductor to the earth

Electrons flow from the earth to the conductor

No charge flow occurs. Top of FormAn uncharged sphere of metal is placed inside a charged parallel plate capacitor. The lines of force look like

Correct option is B

Correct option is A

Correct option is C

Correct option is D

Clear

Bottom of FormAnswer SheetGeneral

1234

5678

9101112

131415

Submit TestPreviousA hollow spherical conductor of radius 2m carries a charge of 500C. Then electric field strength at its surface is

1.125106N/C.

4.5106N/C

2.25106N/C

Zero

ClearA tennis ball which has been covered with charges is suspended by a thread so that it hangs between two metal plates. One plate is earthed, while other is attracted to a high voltage generator. The ball

hangs without moving

is attracted to the high voltage plate and stays there

swings backward & forward hitting each plate in turn

is repelled by earthed plate and stays there.

Clear

A metallic solid sphere is placed in a uniform electric field. In the figure, which path will the lines of force follow?

3.0

1.0

4.0

2.0

Eight dipoles of charges of magnitude e are placed inside a cube. The total electric flux coming out of the cube will be

16eo

A .8eo

eo

Zero

A charge q is placed at the center of the line joining two equal charges Q. The system of the three charges will be in equilibrium if q is equal to

Q/2

Q/4

Q/5

Q/2

Four point chargesqA=2C,qB=5C,qC=2C,andqD=5Care located at the corners of a square ABCD of side 10 cm. Force on a charge of1Cplaced at the centre of the square is

1.8 N

4.5 N

3.6

0 N

A system has two chargesqA=2.5107CandqB=2.5107Clocated at points A: (0, 0, 15 cm) and B: (0,0, +15 cm), respectively. What are the total charge and electric dipole moment of the system?

zero,7.5108Cm

zero,6.5108Cm

zero,5.5108Cm

zero,8.5108Cm

An electric dipole with dipole moment4109Cm is aligned at30with the direction of a uniform electric field of magnitude5104NC1. Calculate the magnitude of the torque acting on the dipole.

3.5104Cm

1.0104Cm

1.5108Nm

2.5104Cm

Two insulated charged copper spheres A and B have their centres separated by a distance of 50 cm. What is the mutual force of electrostatic repulsion if the charge on each is6.5107C? The radii of A and B are negligible compared to the distance of separation.

B2.5102N

3.5102N

1.5102N

4.5102N

Clear

Two insulated charged copper spheres A and B have their centres separated by a distance of 50 cm and have identical sizes. A third sphere of the same size but uncharged is brought in contact with the first, then brought in contact with the second, and finally removed from both. What is the new force of repulsion between A and B?

A3.7103/N

6.7103/N

5.7103/N

4.7103/N

Consider a uniform electric fieldE=3103N/C. (a) What is the flux of this field through a square of 10 cm on a side whose plane is parallel to the yz plane? (b) What is the flux through the same square if the normal to its plane makes a60angle with the x-axis?

40Nm2/C,25Nm2/C

40Nm2/C,15Nm2/C

30Nm2/C,15Nm2/C

A20Nm2/C,15Nm2/C

Clear

Careful measurement of the electric field at the surface of a black box indicates that the net outward flux through the surface of the box is8.0103Nm2/C. (a) What is the net charge inside the box? (b) If the net outward flux through the surface of the box were zero, could you conclude that there were no charges inside the box?

0.05C, No

0.07C, No

0.06C, Yes

A 0.04C, Yes

A point charge of 2.0Cis at the centre of a cubic Gaussian surface 9.0 cm on edge. What is the net electric flux through the surface?

2.2105Nm2/C

2.1105Nm2/C

A1.7105Nm2/C

1.9105Nm2/C

Clear

point charge causes an electric flux of1.0103Nm2/Cto pass through a spherical Gaussian surface of 10.0 cm radius centred on the charge. (a) If the radius of the Gaussian surface were doubled, how much flux would pass through the surface? (b) What is the value of the point charge?

B103Nm2/C,8.8nC

103Nm2/C,6.8nC

103Nm2/C,7.8nC

103Nm2/C,8.8nC

A point charge + q is placed at the mid point of a cube of side L. The electric flux emerging from the cube is

qo

zero

q6L2o

qL2o

A uniformly charged conducting sphere of 2.4 m diameter has a surface charge density of80.0C/m2. (a) Find the charge on the sphere. (b) What is the total electric flux leaving the surface of the sphere?

1.35103C,1.6108Nm2/C

1.45103C,1.6108Nm2/C

1.55103C,1.6108Nm2/C

A1.25103C,1.2108Nm2/C

Clear

Gravitational force is the smallest between

two pens weighing 100gms at a distance of 0.4 m

earth and the sun

earth and the sun

two books of weight 1kg each at a distance of 1 m

Clear

A solid metallic sphere has a charge + 3Q. Concentric with this sphere is a conducting spherical shell having charge Q. The radius of the sphere is a and that of spherical shell is b (b>a). The electric field at a distance R(a