Electricity Book Back Questions 10th Science Lesson 4

10th Science Lesson 4

4] Electricity

Book Back Questions with Answer and Do You Know Box Content

Do You Know?

Nichrome is a conductor with highest resistivity equal to 1.5 x 10^-6Ω m. Hence, it is used in making heating elements.

HORSE POWER: The horse power (hp) is a unit in the foot-pound-second (fps) or English system, sometimes used to express the electrical power. It is equal to 746 watts.

In India, domestic circuits are supplied with an alternating current of potential 220/230 V and frequency 50 Hz. In countries like USA and UK, domestic circuits are supplied with an alternating current of potential 110/120 V and frequency 60 Hz.

Choose the best answers:

1. Which of the following is correct?

(a) Rate of change of charge is electrical power

(b) Rate of change of charge is current

(c) Rate of change of energy is current

(d) Rate of change of current is charge

2. SI unit of resistance if

(a) mho

(b) joule

(c) ohm

(d) ohm meter

3. In a simple circuit, why does the bulb glow when you close the switch?

(a) The switch produces electricity

(b) Closing the switch completes the circuit

(c) Closing the switch breaks the circuit

(d) The bulb is getting charged

4. Kilowatt hour is the unit of

(a) Resistivity

(b) Conductivity

(c) Electrical energy

(d) Electrical power

Fill in the blanks:

1. When a circuit is open, ______________ cannot pass through it.

a. charge

b. energy

c. power

d. current

2. The ratio of the potential difference to the current is known as __________________.

a. Voltage

b. electric potential

c. power

d. resistance

3. The wiring in a house consists of ________________ circuit.

a. domestic

b. industrial

c. home

d. building

4. The power of an electric device is a product of _________________ and ________________.

a. electric charge, resistance

b. electric current, resistance

c. electric charge, potential difference

d. electric current, potential difference

5. LED stands for _____________________.

a. Light Extracting Device

b. Light Emitting Diode

c. Light Emitting Device

d. Light Extracting Diode

State true or false. If false, correct the statement:

1. Ohm’s law states the relationship between power and voltage.

2. MCB is used to protect house hold electrical appliances.

3. The SI unit for electric current is the coulomb.

4. One unit of electrical energy consumed is equal to 1000 kilowatt hour.

5. The effective resistance of three resistors connected in series is lesser than the lowest of the individual resistances.

Match the items in column – I to the items in column – II:

Column – I Column – II

(i) Electric current – volt

(ii) Potential difference – ohm meter

(iii) Specific resistance – watt

(iv) Electrical power – joule

(v) Electrical energy – ampere

Consider the statements given below and choose the correct option:

Mark the correct choice as

(a) If both assertion and reason are true and reason is the correct explanation of assertion

(b) If both assertion and reason are true but reason is not the correct explanation of assertion

(c) If assertion is true but reason is false

(d) If assertion is false but reason is true

1. Assertion: Electric appliances with a metallic body have three wire connections.

Reason: Three pin connections reduce heating of the connecting wires.

2.Assertion: In a simple battery circuit the point of highest potential is the positive terminal of the battery.

Reason: The current flows towards the point of the highest potential.

3.Assertion: LED bulbs are far better than incandescent bulbs.

Reason: LED bulbs consume less power than incandescent bulbs.

Answers:

Choose the best answers:

1.Rate of change of charge is current 2. Ohm 3. Closing the switch closes the circuit 4.Electrical Energy

Fill in the Blanks:

1.Current 2. Resistance 3. Domestic circuit 4. Electric current and Potential difference 5.Light Emitting Diode

True or False:

1.False (Ohm’s law states that relationship between current and voltage).

2.True

3.False (The SI unit of electric current is Ampere(A) )

4.False (One unit = One Kwh)

5.False (The effective resistance is greater than the resistance of Individual resistors)

Match the following:

i) Ampere ii) Volt iii) ohm meter iv) Joule v) Watt

Assertion and Reason:

1.Assertion is true but reason is false.

2.Assertion is true but reason is false.

3.Both assertion and reason are true and reason is the correct explanation of assertion.