electric charges

Question 1

The name electricity is coined from Greek word and its meaning

Answer 1

elektron, amber

Question 2

Electric charges acquire an electric charge on

Answer 2

Rubbing

Question 3

What are the two kinds of electrification ?

Answer 3

like charges repel ; unlike charges attract

Question 4

Define polarity of charges

Answer 4

The property which differentiates the two kinds of charges

Question 5

What effect does unlike charges acquired by the objects have ?

Answer 5

neutralize or nullify each others effect

Question 6

charges were named +ve and -ve by which person ?

Answer 6

american scientist benjamin franklin

Question 7

what is the apparatus to detect charge on a body ? describe it

Answer 7

gold leaf electroscope.
it consists of vertical metal rod housed in a box with two thin gold leaves attached to its bottom end. when charge object touches metal knob at top of rod, charge flows on to leaves and they diverge

Question 8

degree of divergence is indicator of what ?

Answer 8

amount of charge

Question 9

substances which allow free movement of electrons ?

Answer 9

conductors

Question 10

substances which offer high resistance to the passage of electricity through them

Answer 10

insulators

Question 11

The attraction is the real proof of an object being charged. true or false

Answer 11

false.
If an object is attracted by another charged body, the first object may be oppositely charged or not charged because we know both an uncharged object and an oppositely charged object are attracted by another charged object.

Question 12

if system contains n charges of q1, q2, q3…qn the total charge of system

Answer 12

q1+q2+q3+q4….+qn

Question 13

name the one difference between charge and mass

Answer 13

mass of a body is always +ve while charge of a body can be +ve, -ve

Question 14

total charge of isolated system is always

Answer 14

CONSERVED!!!!

Question 15

PONDER ON QUESTION:
fact: it is not possible to create or destroy net charge carried by isolated system although charge carrying particles may be created or destroyed

Answer 15

like when a neutron gets changed into proton or electron

Question 16

unit of charge and value of basic unit of charge

Answer 16

coulomb,
1.6 * 10^-19 C

Question 17

If an object is positively charged, theoretically the mass of the object

Answer 17

Decreases slightly by a factor of 9.1110^-31 kg.
If an object is positively charged it loses some of its electrons. The mass of an electron is 9.1110^-31 kg. So, if a positively charged body loses ‘n’ number of electrons, it mass decreases slightly by a factor of 9.11*10^-31 kg

Question 18

Why is gold used in the Gold-leaf electroscope?

Answer 18

Gold is malleable.
Though gold is a costly metal it is used in electroscope because of the property malleability. This means very thin and light sheets can be formed from gold simply by hammering or rolling and hence the deflection of the light gold plates increases.

Question 19

What happens to the plates of the apparatus if we measure alternating charge using a Gold-leaf oscilloscope?

Answer 19

The plates give a proper divergence.
The divergence of the plates of the Gold-leaf oscilloscope depends only on the presence of a charge, not on the quality of charge i.e. positive or negative. So, if the charge changes from positive to negative and vice versa the degree of divergence of the plates remains the same

Question 20

Dr. Gilbert tried to hold a brass rod by hand and induce static electricity in it by friction. Why did he fail?

Answer 20

The induced static charge flew through his hand and body to the ground.
The human body is a good conductor and hence the charge produced by friction flew through his body to the ground. We can tackle the problem simply by holding the brass rod with the help of some insulated holder