A polythene piece rubbed with wool is found to have a negative charge of 3 . 2 × 10 - 7 C . Find the> (a) number of electrons transferred. (b) mass gained by the polythene.

Given, Net charge on polythene, Q = 3 . 2 × 10 - 7 C (a) According to Quantization of electric charge, Net charge on polythene is integral multiple of basic charge ⇒ Q = n e where n is number of electron transferred and e is charge on an electron ⇒ n = Q e = 3 . 2 × 10 - 7 1 . 6 × 10 - 19 = 2 × 10 12 (b) We know, mass of an electron, m e = 9 . 1 × 10 - 31 kg Mass gained by the polythene, M = mass of an electron m e × number of electrons transferred n ⇒ M = m e n = 9 . 1 × 10 - 31 × 2 × 10 12 ⇒ M = 1 . 82 × 10 - 18 kg

The electrostatic force of repulsion between two positive ions carrying equal charges is 4 × 10 - 9 N , when their separation is 5 . How many electrons are missing from each?

Given, force of repulsion between two ions, 4 × 10 - 9 N , c harged ions are separated by a distance, d = 5 Å . Using Coulomb's law, we get, F = k q 2 d 2 . Here, k = 1 4 π ε 0 = 9 × 10 9 N m 2 C - 2 ⇒ 4 × 10 - 9 = 9 × 10 9 q 2 5 × 10 - 10 2 ⇒ q = 3 . 33 × 10 - 19 C Now, using principle of quantization of charge, ⇒ q = n e ⇒ n = q e n = 3 . 33 × 10 - 19 C 1 .6 × 10 - 19 C = 2 Hence, the number of electrons missing from each ion is 2 .

EASY

NEET

IMPORTANT

Earn 100

A glass tumbler contains $1$ billion amoeba and two sodium ions are there on the body of each amoeba. Find out the charge contained in the glass.

Important Questions on Electrostatics

EASY

NEET

IMPORTANT

Beta Question Bank for Medical: Physics>Chapter 22 - Electrostatics>BEGINNER'S BOX - 1>Q 6

How many electrons should be removed from a conductor so that it acquires a positive charge of

3.5 nC

MEDIUM

NEET

IMPORTANT

Beta Question Bank for Medical: Physics>Chapter 22 - Electrostatics>BEGINNER'S BOX - 1>Q 7

It is now believed that protons and neutrons (which constitute nuclei of ordinary matter) are themselves built out of more elementary units called quarks. A proton and a neutron consist of three quarks each. Two types of quarks, the so called ‘up’ quark (denoted by

u

) of charge

+ (2 / 3) e,

and the ‘down’ quark (denoted by

d

) of charge

(- 1 / 3) e,

together with electrons build up ordinary matter. (Quarks of other types have also been found which give rise to different unusual varieties of matter.) Suggest a possible quark composition of a proton and neutron.

MEDIUM

NEET

IMPORTANT

Beta Question Bank for Medical: Physics>Chapter 22 - Electrostatics>BEGINNER'S BOX - 1>Q 8

Three parallel metallic plates, each area $A$ are kept as shown in the figure and charges $Q_{1}$ , $Q_{2}$ and $Q_{3}$ are given to them. Edge effects are negligible. Calculate the charges on the two outermost surfaces $a$ and $f$ .

Question Image

EASY

NEET

IMPORTANT

Beta Question Bank for Medical: Physics>Chapter 22 - Electrostatics>BEGINNER'S BOX - 2>Q 1

A polythene piece rubbed with wool is found to have a negative charge of $3.2 \times 10^{- 7} C$ . Find the>

(a) number of electrons transferred.

(b) mass gained by the polythene.

EASY

NEET

IMPORTANT

Beta Question Bank for Medical: Physics>Chapter 22 - Electrostatics>BEGINNER'S BOX - 2>Q 2

Two identical metal spheres $A$ and $B$ placed in contact are supported on insulating stand. What kinds of charge will $A$ and $B$ develop when a negatively charged ebonite rod is brought near $A$ ?

MEDIUM

NEET

IMPORTANT

Beta Question Bank for Medical: Physics>Chapter 22 - Electrostatics>BEGINNER'S BOX - 2>Q 3

Two identical metal spheres carry charges of $+ q$ and $- 2 q$ respectively. When the spheres are separated by a large distance $r$ , the force between them is $F$ . Now the spheres are allowed to touch and then moved back to the same separation. Find the new force of repulsion between them.

MEDIUM

NEET

IMPORTANT

Beta Question Bank for Medical: Physics>Chapter 22 - Electrostatics>BEGINNER'S BOX - 2>Q 4

The electrostatic force of repulsion between two positive ions carrying equal charges is

4 \times 10^{- 9} N

, when their separation is

5

. How many electrons are missing from each?

MEDIUM

NEET

IMPORTANT

Beta Question Bank for Medical: Physics>Chapter 22 - Electrostatics>BEGINNER'S BOX - 2>Q 5

Two identical particles each of mass

M

and charge

Q

are placed a certain distance apart. If they are in equilibrium under mutual gravitational and electric force then calculate the order of

\frac{Q}{M}

in SI units.

A glass tumbler contains 1 billion amoeba and two sodium ions are there on the body of each amoeba. Find out the charge contained in the glass.

Important Questions on Electrostatics

Learn and Prepare for any exam you want !

A glass tumbler contains $1$ billion amoeba and two sodium ions are there on the body of each amoeba. Find out the charge contained in the glass.