1172 + Interview Questions in ELECTRICITY IN GENERAL AWARENESS Page 5 InterviewSolution

201.	Name the instrument used for measuring potential difference.
Answer» Voltmeter is used for measuring the potential difference.

Discussion

202.	Which physical quantity remains constant when resistances are connected in parallel?
Answer» Potential difference (voltage) remains constant.

Discussion

203.	What is an electric fuse? How does it function?A. chemical effect of currentB. magnetic effect of currentC. lighting effect of currentD. heating effect of current
Answer» Correct Answer - D

Discussion

204.	Read the following riddles and answer them. 1. I am used to close-or open the circuit. Who am I? 2. I will give you light. Who am I? 3. I convert chemical energy into electrical energy. Who am I? 4. Without me you cannot connect the electrical components. Who am I?
Answer» 1. Switch 2. Bulb 3. Cell 4. Connecting wires

204.

Read the following riddles and answer them. 1. I am used to close-or open the circuit. Who am I? 2. I will give you light. Who am I? 3. I convert chemical energy into electrical energy. Who am I? 4. Without me you cannot connect the electrical components. Who am I?

Answer»

1. Switch

2. Bulb

3. Cell

4. Connecting wires

Discussion

205.	What is consumed using different electrical appliances, for which electricity bills are paid?
Answer» Electrical energy in kWh which is commercially called a unit of electrical energy. 1kWh = 1kW × 1hr = 1 unit of electricity.

Discussion

206.	How is the ammeter connected in the circuit?
Answer» An ammeter is connected in series in the circuit.

Discussion

207.	The elements of electrical heating devices are usually made of:A. tungstenB. bronzeC. nichromeD. argon
Answer» Correct Answer - C

Discussion

208.	Explain why, filament type electric bulbs are not power efficient
Answer» Filament type electric bulbs are not power efficien because most of the electric power consumed by the filament of a bulb appears as heat and only a small amount of electric power is converted into light.

Discussion

209.	Name two gases which are filled in filament type electric light bulbs.
Answer» Argon and nitrogen.

Discussion

210.	Give examples for electric appliances which work on the property of heat effect of electricity.
Answer» Examples for electric appliances which work on the property of heat effect of electricity: 1. Electric heater 2. Electric iron box 3. Soldering gun 4. Electric kettle 5. Electric rice cooker

210.

Give examples for electric appliances which work on the property of heat effect of electricity.

Answer»

Examples for electric appliances which work on the property of heat effect of electricity:

1. Electric heater

2. Electric iron box

3. Soldering gun

4. Electric kettle

5. Electric rice cooker

Discussion

211.	Why is an ammeter connected in series in an electric circuit?
Answer» It is connected in series so that whole of electric current, which it has to measure, passes through it.

Discussion

212.	Naime the electrical devices used to produce heat?
Answer» Electric iron box, electric heater, geyser, grills, electric cooker etc. are the electrical devices used to produced heat.

Discussion

213.	Name the alloy which is used for making the filament of bulbs.
Answer» Tungsten is used for making the filament of bulbs.

Discussion

214.	Name four appliances which work using electricity.
Answer» 1. an electric iron 2. an electric heater 3. an electric kattle 4. an immersion rod

214.

Name four appliances which work using electricity.

Answer»

1. an electric iron

2. an electric heater

3. an electric kattle

4. an immersion rod

Discussion

215.	Name two devices in which electricity is converted into heat.
Answer» Electric heater and electric iron.

Discussion

216.	Which of the following is likely to be the correct wattage for an electric iron used in our homes?A. 60WB. 250WC. 850WD. 2000W
Answer» Correct Answer - C

Discussion

217.	In which arrangement are the appliances connected in the electric circuit of our homes, Series or Parallel ? Give one reason for your answer.
Answer» Parallel circuit : When the circuit is in parallel, the appliances work independently. This is the reason that in our household wiring system, all the circuits are in parallel. Every appliance when put on, works on its own without the interruption of the other appliance.

Discussion

218.	If you were asked to think of electricity, many favourable and unfavourable images come to your mind. (i) Name the favourable images. (ii) What are the unfavourable images ? (iii) What is common to all these images ?
Answer» (i) lamps, television, computers. (ii) lightning, shock, spark from an overloaded outlet. (iii) Electric energy.

Discussion

219.	Which electric heating devices in your home do you think have resistors which control the flow of electricity ?
Answer» Electric iron , electric oven, water heater, room heater.

Discussion

220.	If there is a power failure only in your house. What do you check first?
Answer» We will check the fuse first.

Discussion

221.	List out the electric devices used in your homes
Answer» 1) TV 2) Fans 3) CFL bulbs 4) LED bulbs 5) Tube light (LED) 6) Music system 7) Chargers 8) Refrigerator 9) Electric geyser 10) Vapourizer 11) Iron box 12) Calling bell 13) Mixie 14) Wet grinder 15) AC 16) Motor pump 17) Mosquito repellent.

221.

List out the electric devices used in your homes

Answer»

1) TV

2) Fans

3) CFL bulbs

4) LED bulbs

5) Tube light (LED)

6) Music system

7) Chargers

8) Refrigerator

9) Electric geyser

10) Vapourizer

11) Iron box

12) Calling bell

13) Mixie

14) Wet grinder

15) AC

16) Motor pump

17) Mosquito repellent.

Discussion

222.	Two bulbs of `100 W` each and two coolers of `250 W` each, work on an average `6` hours a day. If the energy costs Rs. `1.75 per kWh`, calculate the monthly bill and the minimum fuse rating when power is supplied at `250 V`.
Answer» Correct Answer - `Rs.220.50, 2.8 A` Total power, `P = (2 xx 100 + 2 xx 250) W = 700 W` Electric energy consumed per month `= P xx t = (700 W)(6 h)(30)` =`126000 Wh = 126 kWh` Monthly bill `= (126 kWh) (Rs. 1.75//kWh) = Rs. 220.50` As `P = VI, I` (minimum fuse rating) `= (P)/(V) = (700 W)/(250 V) = 2.8 A`.

Discussion

223.	From where does the electricity come to our home ?
Answer» In our home's electricity comes from the CITY SUBSTATION.

Discussion

224.	Is there any protection provided for electric devices in our house?
Answer» Yes. The fuse is used to protect the electric devices in our house.

Discussion

225.	Suppose in a house there are four bulbs of 100 W each, six of 60 W each and six of 40 W each. All of them are used for two hours a day. How many units of electricity will be used up in 30 days? How much will they have to pay at Rs. 2.80/- per unit.
Answer» 1. Total power used = (4 × 100 W) + (6 × 60 W) + (6 × 40 W) = 1000 W = 1 KW 2. Total power used every day = 2 hrs × 1 KW = 2 KWH In 30 days, power used = 2 × 30 KWH = 60 KWH 3. The cost of the power is = Rs. 2.80 × 60 = Rs. 168/-

225.

Suppose in a house there are four bulbs of 100 W each, six of 60 W each and six of 40 W each. All of them are used for two hours a day. How many units of electricity will be used up in 30 days? How much will they have to pay at Rs. 2.80/- per unit.

Answer»

1. Total power used = (4 × 100 W) + (6 × 60 W) + (6 × 40 W) = 1000 W = 1 KW

2. Total power used every day = 2 hrs × 1 KW = 2 KWH In 30 days, power used = 2 × 30 KWH = 60 KWH

3. The cost of the power is = Rs. 2.80 × 60 = Rs. 168/-

Discussion

226.	The diagram below in figure shows the reading on the dials of a meter. State what is its reading.
Answer» The reading 2 7 8 9 is 2 7 8 9

226.

The diagram below in figure shows the reading on the dials of a meter. State what is its reading.

Answer»

The reading 2 7 8 9

is 2 7 8 9

Discussion

227.	What is an electric meter ? Where is it fixed in our house ?
Answer» ELECTRIC METER: Is ENERGY meter or kWh meter and measures the amount of electric energy consumed in kWh for which electricity bill is paid. It is connected through a cable after the company fuse on the front or outside wall of the house.

227.

What is an electric meter ? Where is it fixed in our house ?

Answer»

ELECTRIC METER: Is ENERGY meter or kWh meter and measures the amount of electric energy consumed in kWh for which electricity bill is paid.

It is connected through a cable after the company fuse on the front or outside wall of the house.

Discussion

228.

The meter reading in Ayub’s house in January is 400 units, February 580 units. Calculate how much his parents would have to pay towards electricity bill of February. The unit cost is Rs. 3.05.

Answer»

Reading on January 1st	400 Units
Reading on February 1st	580 Units
Number of units Electricity Used	180 Units
Cost per unit	Rs. 3.05/
Total Amount to be paid	180 × 3.05 = 549/

Discussion

229.	Have you seen the electric meter in your house? What do you find in the meter?
Answer» I find reading of consumed electricity in units.

Discussion

230.	For which unit do we pay our electricity bill ?
Answer» UNIT — is boad of trade unit i. e. kWh = 1000 W used in 1 hour.

Discussion

231.	A 60 W bulb is switched on for 5 hours daily. If the cost of electricity is Rs. 3 per unit, calculate the bill for the month of April.
Answer» Energy consumed by the bulb daily `=60 W xx 5 h ` ` = 300 W ` h Energy consumed in the month of April is `300 W h xx 30` `=9000 W h ` `=9 k W h ` cost `= 9 K W h xx Rs. 3 = Rs. 27`

Discussion

232.	The purpose of an electric meter in a house is1. to give the cost of electricity directly2. to give the consumption of electrical energy3. to safeguard the circuit from short circuiting4. to put on or off the mains.
Answer» The purpose of an electric meter in a house is to give the consumption of electrical energy.

Discussion

233.	Fill in the blanks(a) The unit in which we pay the cost of electricity is.................. (b) The electrical energy consumed in a house is measured by..............(c) In a household electrical circuit, the appliance are connected in................with the mains.(d) A switch is connected to the...............wire.(e) The red color insulated wire in a cable is the............. wire.(f) One kilowatt hour is equal to............joule.(g) A fuse wire should have low................
Answer» (a) The unit in which we pay the cost of electricity is kWh. (b) The electrical energy consumed in a house is measured by kWh meter. (c) In a household electrical circuit, the appliance are connected in parallel with the mains. (d) A switch is connected to the live wire. (e) The red colour insulated wire in a cable is the live wire. (f) One kilowatt hour is equal to 3.6 x 106 joule. (g) A fuse wire should have low melting point.

233.

Fill in the blanks(a) The unit in which we pay the cost of electricity is.................. (b) The electrical energy consumed in a house is measured by..............(c) In a household electrical circuit, the appliance are connected in................with the mains.(d) A switch is connected to the...............wire.(e) The red color insulated wire in a cable is the............. wire.(f) One kilowatt hour is equal to............joule.(g) A fuse wire should have low................

Answer»

(a) The unit in which we pay the cost of electricity is kWh.

(b) The electrical energy consumed in a house is measured by kWh meter.

(c) In a household electrical circuit, the appliance are connected in parallel with the mains.

(d) A switch is connected to the live wire.

(e) The red colour insulated wire in a cable is the live wire.

(f) One kilowatt hour is equal to 3.6 x 106 joule.

(g) A fuse wire should have low melting point.

Discussion

234.	When switch of an electric appliance is put off, it disconnects1. the live wire2. the neutral wire3. the earth wire4. the live and the neutral wire
Answer» When switch of an electric appliance is put off, it disconnects the live wire.

Discussion

235.	When no charge is supplied to or removed from a neutral body, then the amount of _____.A. positive charge = negative charge present in itB. positive charge `gt` negative charge present in itC. positive charge `lt` negative charge present in itD. no charge is present in the body initially.
Answer» Correct Answer - A

Discussion

236.	Write true or false for the statementA switch is connected to the neutral wire.
Answer» False A switch is connected to the neutral wire.

Discussion

237.	What is an electric fuse ? Why it is used in electric circuits ? Should it be placed on natural wire or on live wire ? justify your answer.
Answer» An electric fuse is a low resistance resistor that provides protection in the event of a overload current. Rest answer refers to know the terms fuse-wire. It is should be placed on the live wire.

237.

What is an electric fuse ? Why it is used in electric circuits ? Should it be placed on natural wire or on live wire ? justify your answer.

Answer»

An electric fuse is a low resistance resistor that provides protection in the event of a overload current.

Rest answer refers to know the terms fuse-wire. It is should be placed on the live wire.

Discussion

238.	Write true or false for the statementA fuse is connected to the live wire.
Answer» True A fuse is connected to the live wire.

Discussion

239.	What are live and neutral wires ?
Answer» Electrical energy is supplied to houses through two wires, live and neutral wires. If any appliance is to the electrical energy. One end of the appliance is to be connected to a live wire and other end of the appli-ance is to be connected to a neutral wire. Electric current passes from the live wire to neutral wire through the appliance. In this process, electrical energy is converted to other forms of energy.

Discussion

240.	With which wire: live or neutral is the fuse wire connected?
Answer» Fuse is connected with LIVE WIRE.

Discussion

241.	What are the colours of live, neutral and earth wires?
Answer» Electrical energy is supplied to houses through two wires, live and neutral wires. If any appliance is to the electrical energy. One end of the appliance is to be connected to a live wire and other end of the appli-ance is to be connected to a neutral wire. Electric current passes from the live wire to neutral wire through the appliance. In this process, electrical energy is converted to other forms of energy.

Discussion

242.	To the terminals marked as `X and Y` in the given circuit, three students connect `4 ` cells of voltage `1.5 V` each in three different manners (A),(B), (C) shown in (Fig. 3.62). Find the readings `(V_A, V_B, V_C)` of the voltmeter, for the three students. .
Answer» As in (A), all the four cells are in series, in (B), only two cells are effectively in series and in ( C), onle one cell is effective, `V_A = 6.0 V, V_B = 3.0 V, V_C = 1.5 V`.

Discussion

243.	Which one of the given four milliammeters shown in (Fig. 3.60) would you use for measurement of current flowing in a circuit ?
Answer» `II` as it has the smallest least count.

Discussion

244.	The rest positions of the needles in a miliammeter and voltmeter not in use are as shown in (Fig. 3.61)(a). When a student uses these in his experiment, the readings of the needles are in the positions shown in (Fig. 3.61)(b). Find the corrected values of current and voltage in the experiment. .
Answer» As zero correction in milliammeter `= 4 mA` , the correct value of current is `38 mA + 4 mA = 42 mA`. Further, as zero correction in voltmeter `= - 0.4 V`. The correct value of voltage is `3.6 V - 0.4 V = 3.2 V`.

Discussion

245.	A negligibly small current is passes through a wire of length `15 m` and of uniform cross-section `6.0 xx 10%-7 m^2` and its resistance is measured to be `5.0 Omega`. What is the resistivity of the material at the temperature of the experiment ?
Answer» Correct Answer - `2.0 xx 10^-7 ohm m` As `R = rho (l)/(A), rho = (RA)/(l) = ((5.0 Omega)(6.0 xx 10^-7 cm^2))/(15 cm) = 2.0 xx 10^-7 Omega m`.

Discussion

246.	The p.d. across a `3Omega` resistor is 6V. The current flowing in the resistor will be:A. `(1)/(2)A`B. `1A`C. `2A`D. `6A`
Answer» Correct Answer - C

Discussion

247.	When a `12 V` battery is connected across an unknown resistor, there is a current of `2.5 mA` in the circuit. Find the value of the resistance of the resistor.
Answer» Here, `V = 12 V, I = 25 mA = 2.5 xx 10^-3 A` Resistance of the resistor, `R = (V)/(I) = (12 V)/(2.5 xx 10^-3 A) = 4800 Omega = 4.8 k Omega`.

Discussion

248.	When a 12 V battery is connected across an unknown resistor, there is a current of 2.5 mA in the circuit. Find the value of the resistance of the resistor.
Answer» Here I = 2.5 mA = 2.5 × 10^-3 A. ∴ R = \(\frac{12}{25\times 10^{-3}}\) = 4.8 × 10³Ω = 4.8 K cal.

248.

When a 12 V battery is connected across an unknown resistor, there is a current of 2.5 mA in the circuit. Find the value of the resistance of the resistor.

Answer»

Here I = 2.5 mA = 2.5 × 10^-3 A.

∴ R = \(\frac{12}{25\times 10^{-3}}\)

= 4.8 × 10³Ω

= 4.8 K cal.

Discussion

249.	What are the differences between the flow of electric current through metal conductors and electrolytes?
Answer» Compare the electric current carriers in conductors and electrolytes. What is the role of electrodes in an electrolyte? How do the anions and cations move inside an electrolyte? Compare it with the movement of electrons in conductors.

Discussion

250.	During the electrolysis process 4 A electric current flows through a copper sulphate solution for 5 minutes. Determine the number of copper atoms deposited at the cathode.
Answer» Current `I=(q)/(t)`

Discussion

Explore topic-wise InterviewSolutions in .

Name the instrument used for measuring potential difference.

Which physical quantity remains constant when resistances are connected in parallel?

What is an electric fuse? How does it function?A. chemical effect of currentB. magnetic effect of currentC. lighting effect of currentD. heating effect of current

Read the following riddles and answer them. 1. I am used to close-or open the circuit. Who am I? 2. I will give you light. Who am I? 3. I convert chemical energy into electrical energy. Who am I? 4. Without me you cannot connect the electrical components. Who am I?

What is consumed using different electrical appliances, for which electricity bills are paid?

How is the ammeter connected in the circuit?

The elements of electrical heating devices are usually made of:A. tungstenB. bronzeC. nichromeD. argon

Explain why, filament type electric bulbs are not power efficient

Name two gases which are filled in filament type electric light bulbs.

Give examples for electric appliances which work on the property of heat effect of electricity.

Why is an ammeter connected in series in an electric circuit?

Naime the electrical devices used to produce heat?

Name the alloy which is used for making the filament of bulbs.

Name four appliances which work using electricity.

Name two devices in which electricity is converted into heat.

Which of the following is likely to be the correct wattage for an electric iron used in our homes?A. 60WB. 250WC. 850WD. 2000W

In which arrangement are the appliances connected in the electric circuit of our homes, Series or Parallel ? Give one reason for your answer.

If you were asked to think of electricity, many favourable and unfavourable images come to your mind. (i) Name the favourable images. (ii) What are the unfavourable images ? (iii) What is common to all these images ?

Which electric heating devices in your home do you think have resistors which control the flow of electricity ?

If there is a power failure only in your house. What do you check first?

List out the electric devices used in your homes

Two bulbs of `100 W` each and two coolers of `250 W` each, work on an average `6` hours a day. If the energy costs Rs. `1.75 per kWh`, calculate the monthly bill and the minimum fuse rating when power is supplied at `250 V`.

From where does the electricity come to our home ?

Is there any protection provided for electric devices in our house?

Suppose in a house there are four bulbs of 100 W each, six of 60 W each and six of 40 W each. All of them are used for two hours a day. How many units of electricity will be used up in 30 days? How much will they have to pay at Rs. 2.80/- per unit.

The diagram below in figure shows the reading on the dials of a meter. State what is its reading.

What is an electric meter ? Where is it fixed in our house ?

The meter reading in Ayub’s house in January is 400 units, February 580 units. Calculate how much his parents would have to pay towards electricity bill of February. The unit cost is Rs. 3.05.

Have you seen the electric meter in your house? What do you find in the meter?

For which unit do we pay our electricity bill ?

A 60 W bulb is switched on for 5 hours daily. If the cost of electricity is Rs. 3 per unit, calculate the bill for the month of April.

The purpose of an electric meter in a house is1. to give the cost of electricity directly2. to give the consumption of electrical energy3. to safeguard the circuit from short circuiting4. to put on or off the mains.

When switch of an electric appliance is put off, it disconnects1. the live wire2. the neutral wire3. the earth wire4. the live and the neutral wire

When no charge is supplied to or removed from a neutral body, then the amount of _____.A. positive charge = negative charge present in itB. positive charge `gt` negative charge present in itC. positive charge `lt` negative charge present in itD. no charge is present in the body initially.

Write true or false for the statementA switch is connected to the neutral wire.

What is an electric fuse ? Why it is used in electric circuits ? Should it be placed on natural wire or on live wire ? justify your answer.

Write true or false for the statementA fuse is connected to the live wire.

What are live and neutral wires ?

With which wire: live or neutral is the fuse wire connected?

What are the colours of live, neutral and earth wires?

To the terminals marked as `X and Y` in the given circuit, three students connect `4 ` cells of voltage `1.5 V` each in three different manners (A),(B), (C) shown in (Fig. 3.62). Find the readings `(V_A, V_B, V_C)` of the voltmeter, for the three students. .

Which one of the given four milliammeters shown in (Fig. 3.60) would you use for measurement of current flowing in a circuit ?

The rest positions of the needles in a miliammeter and voltmeter not in use are as shown in (Fig. 3.61)(a). When a student uses these in his experiment, the readings of the needles are in the positions shown in (Fig. 3.61)(b). Find the corrected values of current and voltage in the experiment. .

A negligibly small current is passes through a wire of length `15 m` and of uniform cross-section `6.0 xx 10%-7 m^2` and its resistance is measured to be `5.0 Omega`. What is the resistivity of the material at the temperature of the experiment ?

The p.d. across a `3Omega` resistor is 6V. The current flowing in the resistor will be:A. `(1)/(2)A`B. `1A`C. `2A`D. `6A`

When a `12 V` battery is connected across an unknown resistor, there is a current of `2.5 mA` in the circuit. Find the value of the resistance of the resistor.

When a 12 V battery is connected across an unknown resistor, there is a current of 2.5 mA in the circuit. Find the value of the resistance of the resistor.

What are the differences between the flow of electric current through metal conductors and electrolytes?

During the electrolysis process 4 A electric current flows through a copper sulphate solution for 5 minutes. Determine the number of copper atoms deposited at the cathode.