Samacheer Kalvi 9th Term II Science Book Back Question and Answers – Unit 2:

Samacheer Kalvi 9th Standard New Science Book Back 1 Mark and 2 Mark Question & Answers PDF uploaded and available below. Class 9 New Syllabus 2021 to 2022 Book Back Question & Answer solutions available for both English and Tamil Medium. Class 9 Science Book Term 2 Unit 2 – Electric charge and electric current Answers/Solutions are provided on this page. 9th Std Science Book is of Term 1st, 2nd, 3rd, and consists of 9 Units in each Term. All 9 Units of Term 1st, 2nd, 3rd Science Book Back One, and Two Mark Solutions are given below.

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Samacheer Kalvi 9th Science Book Back Unit 2 Term 2 Solutions Guide PDF:

Science Subject 1 Mark and 2 Mark Solutions Guide PDF available below. Click the Download option to download the book back 1 Mark & 2 Mark questions and answers. Take the printout and use it for exam purposes.

Term – 2

Unit – 2

Electric charge and electric current

I. Choose the correct answer:

1. In current electricity, a positive charge refers to,
a) presence of electron
b) presence of proton
c) absence of electron
d) absence of proton

2. Rubbing of comb with hair
a) creates electric charge
b) transfers electric charge
c) either (a) or (b)
d) neither (a) nor (b)

3. Electric field lines ……….. from positive charge and in negative charge.
a) start; start
b) start; end
c) start; end
d) end; end

4. Potential near a change is the measure of its to bring a positive charge at that point.
a) force
b) ability
c) tendency
d) work

5. In an electrolyte the current is due to the flow of
a) electrons
b) positive ions
c) both (a) and (b)
d) neither (a) nor (b)

6. Heating effect of current is called
a) Joule heating
b) Coulomb heating
c) voltage heating
d) Ampere heating

7. The following is not a safety device.
a) fuse
b) trip switch
c) ground connection
d) wire

8. Electroplating is an example for
a) heating effect
b) chemical effect
c) flowing effect
d) magnetic effect

9. Resistance of a wire depends on
a) temperature
b) geometry
c) nature of material
d) all the above

10. In India the frequency of alternating current is
a) 220 Hz
b) 50 Hz
c) 5 Hz
d) 100 Hz

II. Match the following:

1. Electric Charge                    a) ohm
2. Potential difference            b) ampere
3. Electric field                         c) coulomb
4. Resistance                             d) newton per coulomb
5. Electric current                     e) volt
Ans: 1–c; 2-e; 3-d; 4-a; 5-b

III. True or False

I. Electrically neutral means it is either zero or equal positive and negative charges. –True
2. Ammeter is connected in parallel in any electric circuit. –False
3. The anode in electrolyte is negative. –False
4. Current can produce magnetic field. –True
5. Electric fuse works on Joule heating principle. –True

IV. Fill in the blanks:

1 . Electrons move from higher potential to lower potential.
2. The direction opposite to the movement of electron is called conventional current.
3. The e.m.f of a cell is analogues to water pump of a pipe line.
4. The domestic electricity in India is an ac with a frequency of 50 Hz.
5. Trip switch is a electro mechanical safety device.

V. Short Questions & Answers:

1. On what factors does the electrostatic force between two charges depend?
The numerical value (magnitude) of electric force between two charges depend on the
i. value of charges on them.
ii. distance between them and
iii. nature of medium between them.

2. What are electric lines of force?
The electric lines of force are straight or curved paths along which a unit positive charge tends to move in the electric field.

3. Define electric filed.
The region in which a charge experiences electric force forms the ‘electric field’ around the charge.

4. Define electric current and give its unit.
Current is the rate at which charges flow past a point on a circuit. The standard SI unit for current is ampere with the symbol A.

5. State Ohm’s law.
Ohm’s law states that electric potential difference across two points in an electrical circuit is directly proportional to the current passing through it. that is
V ∞ I
The proportionality constant is the resistance (R) offered between the two points.
Hence, Ohm’s law is written as,
V = RI (or) V = IR

6. On what factor does the resistance of a wire depend at a particular temperature?
The resistance offered by a material at a particular temperature depends on the
i) geometry of the material and
ii) nature of the material.

7. Name any two appliances which work under the principle of heating effect of current.
Iron box and water heater work under the principle of heating effect of current.

8. How are the home appliances connected in general, in series or parallel. Give reasons.
Home appliances are connected in parallel because in this type, all other devices will function even if one device becomes faulty.

9. List the safety features wile handling with electricity.
Safety features to be followed are ground connection, trip switch, fuse.

10. Can electroplating be possible with alternating current?
As the +ve and –ve electrodes keep changing, electroplating is not possible with alternating current.

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