Question 11

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?

Answer

Capacitance of the capacitor, *C* = 600 pF

Potential difference, *V* = 200 V

Electrostatic energy stored in the capacitor is given by,

If supply is disconnected from the capacitor and another capacitor of capacitance *C* = 600 pF is connected to it, then equivalent capacitance (*C*^{'}) of the combination is given by,

New electrostatic energy can be calculated as

Loss in electrostatic enegy = *E - E'*

= 1.2 x 10^{-5} - 0.6 x 10^{-5}

= 0.6 x 10^{-5}

= 6 x 10^{-6} J

Therefore, the electrostatic energy lost in the process is 6 x 10^{-6} J.

- 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:-
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:-
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 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 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:-
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 12 pF capacitor is connected to a 50V battery. How much electrostatic energy is stored in the capacitor?

- 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 uniformly charged conducting sphere of 2.4 m diameter has a surface charge density of 80.0 μC/m

^{2}.(a) Find the charge on the sphere.

(b) What is the total electric flux leaving the surface of the sphere?

- Q:- Two charges 2 μC and −2 μC are placed at points A and B 6 cm apart.

(a) Identify an equipotential surface of the system.

(b) What is the direction of the electric field at every point on this surface? - Q:-
What is the magnitude of magnetic force per unit length on a wire carrying a current of 8 A and making an angle of 30º with the direction of a uniform magnetic field of 0.15 T?

- Q:-
Suppose the spheres A and B in Exercise 1.12 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?

- Q:-
The energy flux of sunlight reaching the surface of the earth is 1.388 × 10

^{3}W/m^{2}. How many photons (nearly) per square metre are incident on the Earth per second? Assume that the photons in the sunlight have an average wavelength of 550 nm. - Q:-
At a certain location in Africa, a compass points 12º west of the geographic north. The north tip of the magnetic needle of a dip circle placed in the plane of magnetic meridian points 60º above the horizontal. The horizontal component of the earth's field is measured to be 0.16 G. Specify the direction and magnitude of the earth's field at the location.

- Q:-
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 is 8.0 × 103 N m2/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? Why or Why not?

- 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 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:-
A 12 pF capacitor is connected to a 50V battery. How much electrostatic energy is stored in the capacitor?

- 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?

Anjali Kashyap
2019-07-23 18:58:14

Thank you

Adithya
2019-06-23 19:28:03

common potential =c1c2\\c1+c2

Deepika
2019-06-14 11:05:07

How can we now that it is connected in series

Ameer Navas
2019-06-08 22:37:09

It is parallel not series.

Gode Basar
2019-05-10 07:07:36

How can we know that the capacitors are connected in series?

Nandini
2019-05-08 10:41:10

How can we conclude that capacitors are in series

Vibhor Singh
2018-05-23 00:58:49

In this question it is not written that uncharged capacitor is connected in series then how you take in series according to the solution??

vinay
2018-02-28 07:17:15

what if the unchanged capacitor is connected to parallel with it

- NCERT Chapter

Copyright © 2020 saralstudy.com. All Rights Reserved.