This page focuses on the detailed Electric Charges and Field question answers for Class 12 Physics Electric Charges and Field, addressing the question: 'An electric dipole with dipole moment 4 × 10−9 C m is aligned at 30° with the direction of a uniform electric field of magnitude 5 × 104N C−1. Calculate the magnitude of the torque acting on the dipole.'. The solution provides a thorough breakdown of the question, highlighting key concepts and approaches to arrive at the correct answer. This easy-to-understand explanation will help students develop better problem-solving skills, reinforcing their understanding of the chapter and aiding in exam preparation.

Question 10

An electric dipole with dipole moment 4 × 10^{−9} C m is aligned at 30° with the direction of a uniform electric field of magnitude 5 × 10^{4}N C^{−1}. Calculate the magnitude of the torque acting on the dipole.

Answer

Electric dipole moment, p = 4 × 10^{−9} C m (Given)

Angle made by p with a uniform electric field, θ = 30° (Given)

Electric field, E = 5 × 10^{4} N C^{−1} (Given)

Torque acting on the dipole is given by the relation,

τ = *pE* sin*θ*

= 4 × 10^{-9} × 5 × 10^{4} × sin 30

= 20 × 10^{-5} ×

= 10^{-4} Nm

Therefore, the magnitude of the torque acting on the dipole is 10^{−4} N m.

- Q:-
What is the force between two small charged spheres having charges of 2 x 10

^{-7}C and 3 x 10^{-7}C placed 30 cm apart in air? - Q:-
An infinite line charge produces a field of 9 × 10

^{4}N/C at a distance of 2 cm. Calculate the linear charge density. - Q:-
A polythene piece rubbed with wool is found to have a negative charge of 3 × 10

^{−7}C.(a) Estimate the number of electrons transferred (from which to which?)

(b) Is there a transfer of mass from wool to polythene?

- Q:-
A 600 pF capacitor is charged by a 200 V supply. It is then disconnected from the supply and is connected to another uncharged 600 pF capacitor. How much electrostatic energy is lost in the process?

- Q:-
A parallel plate capacitor with air between the plates has a capacitance of 8 pF (1pF = 10

^{-12}F). What will be the capacitance if the distance between the plates is reduced by half, and the space between them is filled with a substance of dielectric constant 6? - Q:- A circular coil of wire consisting of 100 turns, each of radius 8.0 cm carries a current of 0.40 A. What is the magnitude of the magnetic field B at the centre of the coil?
- Q:-
A regular hexagon of side 10 cm has a charge 5 µC at each of its vertices. Calculate the potential at the centre of the hexagon.

- Q:-
A point charge +10 μC is a distance 5 cm directly above the centre of a square of side 10 cm, as shown in Fig. 1.34. What is the magnitude of the electric flux through the square? (Hint: Think of the square as one face of a cube with edge 10 cm.)

- Q:-
A conducting sphere of radius 10 cm has an unknown charge. If the electric field 20 cm from the centre of the sphere is 1.5 × 10

^{3}N/C and points radially inward, what is the net charge on the sphere? - Q:-
A point charge of 2.0 μC is at the centre of a cubic Gaussian surface 9.0 cm on edge. What is the net electric flux through the surface?

- Q:-
In deriving the single slit diffraction pattern, it was stated that the intensity is zero at angles of nλ/a. Justify this by suitably dividing the slit to bring out the cancellation.

- Q:-
Two charges 5 x 10

^{-8}C and -3 x 10^{-8}C are located 16 cm apart. At what point(s) on the line joining the two charges is the electric potential zero? Take the potential at infinity to be zero. - Q:-
A carrier wave of peak voltage 12 V is used to transmit a message signal. What should be the peak voltage of the modulating signal in order to have a modulation index of 75%?

- Q:-
A point charge causes an electric flux of −1.0 × 10

^{3}Nm^{2}/C to pass through a spherical Gaussian surface of 10.0 cm radius centered 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?

- Q:-
A spherical capacitor consists of two concentric spherical conductors, held in position by suitable insulating supports (Figure). Show

that the capacitance of a spherical capacitor is given by

where

*r*1 and*r*2 are the radii of outer and inner spheres, respectively. - Q:-
The wires which connect the battery of an automobile to its starting motor carry a current of 300 A (for a short time). What is the force per unit length between the wires if they are 70 cm long and 1.5 cm apart? Is the force attractive or repulsive?

- Q:-
In accordance with the Bohr’s model, find the quantum number that characterises the earth’s revolution around the sun in an orbit of radius 1.5 × 10

^{11}m with orbital speed 3 × 10^{4}m/s. (Mass of earth = 6.0 × 10^{24}kg.) - Q:-
A regular hexagon of side 10 cm has a charge 5 µC at each of its vertices. Calculate the potential at the centre of the hexagon.

- Q:-
What is the

(a) momentum,

(b) speed, and

(c) de Broglie wavelength of an electron with kinetic energy of 120 eV.

- Q:-
The work function of caesium metal is 2.14 eV. When light of frequency 6 ×10

^{14}Hz is incident on the metal surface, photoemission of electrons occurs. What is the(a) maximum kinetic energy of the emitted electrons,

(b) Stopping potential, and

(c) maximum speed of the emitted photoelectrons?

Hritik
2019-05-31 06:04:55

Super

Dulen
2019-05-20 20:40:17

What is the potential energy of the given problem?

Pawan
2019-04-21 10:46:57

Nice

Bhumi
2019-04-21 07:33:26

10^-4 kaise aaya hai

Sukriti
2019-04-17 20:46:27

I was little bit confused

Rohan
2018-12-01 16:41:19

Thank you so much

Sahil Singh
2018-10-24 12:37:37

Ya it is too good

Keerthu
2018-04-15 15:23:26

It is very nice

Ralynn
2018-04-09 21:17:13

This is really good

rana singj
2017-12-17 08:56:38

An electric dipole held at an angle of 300 with respect to a Uniform electric field of 4 x 104 N/C experiences a torque of 1.6 x10-25 Nm calculate its dipole Moment

- NCERT Chapter