Electric Field

Q.

Given below are two statements:

Statement – I: An electric dipole is placed at the centre of a hollow sphere. The flux of the electric field through the sphere is zero but the electric field is not zero anywhere in the sphere.

Statement – II: If $R$ is the radius of a solid metallic sphere and $Q$ be the total charge on it. The electric field at any point on the spherical surface of radius $(r<R)$ is zero but the electric flux passing through this closed spherical surface of radius $r$ is not zero.

In the light of the above statements Choose the correct answer from the option given below:

1. Statement I is true but Statement II is false

2. Statement I is false but Statement II is true

3. Both Statement I and Statement II are true

4. Both Statement I and Statement II are false

Q. Two charges +q1 and -q2 are placed at points A and b respectively. A line of force emanates from q1 at an angle alpha with the line AB. At what angle will it terminate at -q2 ?

Q.

The electric field at a distance $\frac{3R}{2}$ of the center of a charged conducting spherical shell of radius $R$ is $E$. The electric field at a distance $\frac{R}{2}$from the center of the sphere is

1. $Zero$

2. $E$

3. $\frac{E}{2}$

4. $\frac{E}{3}$

Q.

How do moving electric charges create magnetic fields?

Q.

Why do equipotential lines get further apart?

Q.

how does current flows in an electrolyte

Q.

A girl is carrying a school bag of $3kg$ mass on her back and moves $200m$ on a levelled road. The work done against the gravitational force will be $(g=10m{s}^{-2})$

1. $6\times {10}^{3}J$

2. $6J$

3. $0.6J$

4. zero

Q. ntQ) A small element l is cut from a circular ring of radius a and lambda charge per unit length. The net electric field at the centre of ring will be ?n ntn

Q.

Give two example of elastic potential energy.

Q.

If we take the analogy between mechanical motion and electric circuits, then inductance is analogous to

Q.

A non-zero force is acting on a body but work done is zero. Which of the following statements justify the above situation?

1. Distance moved is zero.
2. Force is perpendicular to the direction of motion.
3. Force is in the direction of motion.
4. Force is opposite to the direction of motion.

1. 1 and 3

2. 1 and 2

3. 1 and 4

4. 1, 3 and 4

Q. Scientifically, work is said to be done in which of the following cases?

1. Manoj pushes the wall with no change in the position of wall.
2. Manish pulls the trolley for a certain distance.
3. Mira pulls the wall with no change in the position of wall.
4. Mira studies for her exam.

Q. Forces of interaction between two co-axial short electric dipoles whose centres are R distance apart varies as _____________

Q. ntDerive the formulas for the electric field applied on the point placed around the dipole but not on axial or equitorial position.n

Q. A solid metallic sphere is placed in a uniform electric field. Which of the curves shown in figure represent the lines of force correctly?

1. $\left(b\right)$
2. $\left(c\right)$
3. $\left(a\right)$
4. $\left(d\right)$

Q. What is the unit of magnetic field ?

1. H
2. N A m${}^{-1}$
3. N A${}^{-1}$ m
4. N A${}^{-1}$ m${}^{-1}$

Q. A metallic solid sphere is placed in a uniform electric field. The lines of force follow the path(s) shown in Fig. as

1. $2$
2. $1$
3. $3$
4. $4$

Q. Draw a plot showing the variation of (i) electric field (E) and (ii) electric potential (V) with the distance r due to a point charge Q.

Q. The given figure shows the electic line of force. If the electric fields at A, B, C and D are $E_A,E_B,E_C,$ and $E_D$ respectively then

1. $E_A=E_C>E_B=E_D$
2. $E_A=E_B>E_C=E_D$
3. $E_A=E_B=E_C=E_D$
4. $E_A=E_C<E_B=E_D$

Q.

A van is travelling at 52 km/h, when brakes are applied it comes to rest in 5 s. Another van is travelling at 3 km/h and when brakes are applied it comes to rest in 10 s. Plot the speed versus time graph and calculate the braking distance for both the vans? [3 MARKS]

Q. Four point charges qA=2/1000000c, qB=-5/1000000, qC=2/1000000C and qD=-5/1000000 are located at corners of a square ABCD of side 10cm. What is the force on the charge of 1/1000000c placed at the centre of the square.

Q. The variation of potential with distance r from a fixed point is shown in Figure. The electric field at $r=5$cm, is?

1. $\left(2.5\right)V/cm$
2. $(-2.5)V/cm$
3. $(-2/5)cm$
4. $\left(2/5\right)V/cm$

Q. Let the electrostatic force between two electrons $\left(F_e\right)$ be x times the gravitational force $\left(F_g\right)$ between them. Then, x is of the order of?

1. ${10}^{40}$
2. ${10}^{38}$
3. ${10}^{42}$
4. ${10}^{37}$

Q. The electric field due to an infinitely long straight uniformly charged wire at a distance r is directly proportional to

1. r
2. $r^2$
3. $\frac{1}{r}$
4. $\frac{1}{r^2}$

Q. The electric field is $100V/m$, at a distance of $20cm$ from the centre of a dielectric sphere of radius $10cm$. Then $E$ at $3cm$ distance from the centre of sphere is:

1. $100V/m$
2. $125V/m$
3. $120V/m$
4. $zero$

Q.

1. both negative
2. Upper positive and lower negative
3. both positive
4. upper negative and lower positive

Q.

One kilowatt-hour is also known as one unit.

1. True
2. False

Q. Mention any two properties of electric field lines.

Q.

Use the following information to answer the next question.

Two iron balls are charged with a similar type of charge. The nature and the amount of the charge possessed by each ball are shown in the given figure.

If the balls are kept in contact with each other, then what will be the possible distribution of charges between the balls?

1. 

2. 

3. 

4. 

Q. The diagram below represents five different same-length identical wires(red) carrying the same amount of current in the same magnetic field (blue) with current directions and magnetic field directions indicated by arrows.
Which wire(s) experience(s) the most force due to the magnetic field?

1. 2 only
2. 3 only
3. 2 and 5
4. 1 only
5. 1 and 4