Two point charges of + 1 . 0 × 10 - 6 C and - 1 . 0 × 10 - 6 C are at a distance 2 . 0 cm apart from each other. This electric dipole is situated in a uniform electric field of 1 . 0 × 10 5 V - m - 1 . What will be the maximum torque acting on it due to the field? What will be the work done for rotating it through 180 ∘ from the equilibrium position?

Given that q 1 = 1 . 0 × 10 - 6 C and q 1 = q 2 = q ⇒ q 2 = 1 . 0 × 10 - 6 C E = 1 × 10 5 NC - 1 2 r = 2 . 0 cm = 2 × 10 - 2 m r = 2 . 0 cm ∴ P = q 2 r = 1 × 10 - 6 × 2 × 10 - 2 C-m P = 2 × 10 - 8 C-m ∴ torque acting on q due to E → is 𝜏 = PEsinθ θ = 90 ° for max torque ⇒ 𝜏 = 2 × 10 - 8 × 1 × 10 + 5 = 2 × 10 - 3 N - m ∴ 𝜏 = 2 × 10 - 3 N - m Work done in rotating the dipole in uniform electric field . W = PE 1 - cosθ θ = 180 ° = 2 × 10 - 3 1 + 1 = 2 × 2 × 10 - 3 ∴ W = 4 × 10 - 3 J

HARD

12th ICSE

IMPORTANT

Earn 100

Calculate the work required to assemble each of the systems of charges (which is same as the electrostatic potential energy of the system) shown in Fig. $(a)$ and $(b)$ .

Important Questions on Electric Potential

MEDIUM

12th ICSE

IMPORTANT

NOOTAN ISC PHYSICS Class 12 Part-1>Chapter 3 - Electric Potential>QUESTIONS>Q 25

(ii) A charge $q_{0}$ is brought from infinity to the centre of the square, the four charges being held fixed at its comers. How much extra work is needed to do this?

Question Image

HARD

12th ICSE

IMPORTANT

NOOTAN ISC PHYSICS Class 12 Part-1>Chapter 3 - Electric Potential>QUESTIONS>Q 26

The distance between two protons is

1.0 \times 10^{- 10} m

. If they are made free, what will be the kinetic energy of each when they are away at a very large distance from each other? If one proton is kept fixed and only other is free then what will be its kinetic energy?

HARD

12th ICSE

IMPORTANT

NOOTAN ISC PHYSICS Class 12 Part-1>Chapter 3 - Electric Potential>QUESTIONS>Q 27

Two electrons are released towards each other with equal velocities of

10^{6} m s^{- 1}

. What will be the closest approach between them?

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12th ICSE

IMPORTANT

NOOTAN ISC PHYSICS Class 12 Part-1>Chapter 3 - Electric Potential>QUESTIONS>Q 28

Two point charges of

+ 1.0 \times 10^{- 6} C

and

- 1.0 \times 10^{- 6} C

are at a distance

2.0 cm

apart from each other. This electric dipole is situated in a uniform electric field of

1.0 \times 10^{5} V - m^{- 1}

. What will be the maximum torque acting on it due to the field? What will be the work done for rotating it through

180^{\circ}

from the equilibrium position?

HARD

12th ICSE

IMPORTANT

NOOTAN ISC PHYSICS Class 12 Part-1>Chapter 3 - Electric Potential>QUESTIONS>Q 29

An electric dipole of length

2 cm

is placed with its axis making an angle of

60^{\circ}

to a uniform electric field of

10^{5} N ‐ C^{- 1}

. If it experiences a torque of

8 \sqrt{3} N ‐ m,

calculate magnitude of the charge on the dipole.

EASY

12th ICSE

IMPORTANT

NOOTAN ISC PHYSICS Class 12 Part-1>Chapter 3 - Electric Potential>QUESTIONS>Q 29

An electric dipole of length

2 cm

is placed with its axis making an angle of

60 °

to a uniform electric field of

10^{5} N - C^{- 1}

. If it experiences a torque of

8 \sqrt{3} N - m

, calculate potential energy of the dipole.

HARD

12th ICSE

IMPORTANT

NOOTAN ISC PHYSICS Class 12 Part-1>Chapter 3 - Electric Potential>QUESTIONS>Q 30

Two point charges of

+ 3 μC

and

- 3 μC

are at a distance

3 \times 10^{- 3} m

apart from each other. Calculate electric potential at a distance of

0.6 m

from the dipole in broad-side-on position.

HARD

12th ICSE

IMPORTANT

NOOTAN ISC PHYSICS Class 12 Part-1>Chapter 3 - Electric Potential>QUESTIONS>Q 30

Two point charges of

+ 3 μC

and

- 3 μC

are at a distance

3 \times 10^{- 3} m

apart from each other. Calculate the electric potential at distance of 0.6m from the dipole in broad-side on position and at the same point after rotating the dipole through

90 °

Calculate the work required to assemble each of the systems of charges (which is same as the electrostatic potential energy of the system) shown in Fig. (a) and (b).

Important Questions on Electric Potential

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Calculate the work required to assemble each of the systems of charges (which is same as the electrostatic potential energy of the system) shown in Fig. $(a)$ and $(b)$ .