AMU, BHU, JMI, DBRAU Papers and Notes – Notesavailable ## NCERT Solutions for Class 12 Physics Chapter 1 – Free PDF Download

The NCERT Answers for Class 12 Physical science Section 1 Electric Charges and Fields are given here to assist understudies with getting ready well for the Class 12 CBSE Board test, as well as aggressive tests like JEE and that’s just the beginning. Here, in these NCERT Answers for Class 12 Material science, understudies can track down addressed deals with Electric Charges and Fields from Class 12, alongside significant inquiries from earlier year question papers, model issues, MCQs, worksheets and activities that will assist them with planning for serious tests too.

These NCERT Answers for Class 12 Physical science will likewise assist you with going through the essentials, and you ought to anticipate somewhere around one inquiry in your board test from this section. It is not difficult to get ready Electric Charges and Fields Class 12 notes by rehearsing these arrangements. Download now the PDF of NCERT Answers for Class 12 Material science Part 1 from the connection beneath.

## NCERT Solutions for Class 12 Physics Chapter 1 Electric Charges and Fields

### Class 12 Physics NCERT Solutions for Chapter 1 Electric Charges and Fields – Important Questions

Q 1.1) What is the force between two small charged spheres having charges of 2 × 10–7C and 3 × 10–7 C placed 30 cm apart in the air?

Soln: Given,

The charge on the 1st sphere and 2nd sphere is q1 = 2 x 10-7 C and q2 = 3 x 10-7 C

The distance between two charges is given by r = 30cm = 0.3m

The electrostatic force between the spheres is given by the relation:

F =

Here,

= permittivity of free space and,

= 9 x 109 Nm2C-2

Force, F =

9×109×2×10−7×3×10−7(0.3)2

= 6 x 10‑3 N.

The force between the charges will be repulsive as they have the same nature.

Q 1.2) The electrostatic force on a small sphere of charge is 0.4 µC due to another small sphere of charge –0.8 µC in the air is 0.2 N.

(a) What is the distance between the two spheres?

(b) What is the force on the second sphere due to the first?

Soln:

(a) Given,

The charge on the 1st sphere (q) and the 2nd sphere (q2) is 0.4 µC or 0.4 × 10-6 C and -0.8 × 10-6C, respectively.

The electrostatic force on the 1st sphere is given by F = 0.2N.

The electrostatic force between the spheres is given by the relation:

F =

Here,

= permittivity of free space and,

= 9 × 109 Nm2C-2

r2 =

=

0.4×10−6×8×10−6×9×1090.2

= 144 x 10-4

r =

144×10−4

= 12 x 10-2 = 0.12m

Therefore, the distance between the two spheres = 0.12 m

(b) Since the spheres have opposite charges, the force on the second sphere due to the first sphere will also be equal to 0.2N.