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InterviewSolution
This section includes InterviewSolutions, each offering curated multiple-choice questions to sharpen your knowledge and support exam preparation. Choose a topic below to get started.
| 351. |
The device used for producting electric current is called a :A. speedometerB. ammeterC. voltmeterD. kilowat hour meter |
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Answer» Correct Answer - B The device used to measure electric currentin a cir-cuit is "Ammeter". |
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| 352. |
What happens if the switch is open in the experiment of given picture. |
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Answer» When we switched off the circuit, immediately all the pins fall from the iron nail. |
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| 353. |
Fill in the table with suitable answers.Name of the DeviceUseTo give lightSwitchTo protect from high voltageCell |
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| 354. |
The resistivity does not change if :A. the material is changedB. the temperature is changedC. the shape of the resistor is changedD. both material and temperature are changed |
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Answer» Correct Answer - C Resistivity depends on the nature of the material and the temperature but does not depend on the shape of the resistor. |
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| 355. |
In an electrical circuit three incandescent bulbs `A,B and C` of rating `40 W, 60 W and 100 W` respectively are connected in parallel to an electric source. Which of the following is likely to happen regarding their brightness ?A. Brightness of all the bulbs will be the sameB. Brightness of bulb A will be the maximumC. Brightness of bulb B will be more than that of AD. Brightness of bulb C will be less than that of B |
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Answer» Correct Answer - C In an electrical circuit, three incandescent bulbs A, B and C of rating 40 W, 60 W and 100 W are connected in parallel to an electric source, then the bulb w9th the highest wattage glows with maximum brightness. Power dissipated `prop` Brightness. Thus, the this brightness different bulks are in following order `B_(100) gt B_(60) gt B_(40)`. |
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| 356. |
A safety device used to avoid fire when excessive electric current flows through a circuit is called a ………… A) Bulb B) Fuse C) Inverter D) Power bank |
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Answer» Correct option is B) Fuse |
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| 357. |
What is a cell? How does it work? |
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Answer» A cell is a device used to generate electricity. It mainly consists of two components. 1. Electrolyte – This is a chemical component that conducts the electricity. 2. Electrodes – There are two electrodes in a ceiL One is positive electrode called anode and the other is negative electrode called cathode. When electrodes come in contact with electrolyte, a chemical reaction takes place inside the cell to produce electricity. Thus, it converts the chemical energy into electrical energy When electrodes are connected to the wires in a circuit, electricity passes through them. |
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| 358. |
After studying the lesson electricity and its effect what safety device do you use in electric circuit? A) Bulb B) Battery C) Switch D) Fuse |
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Answer» Correct option is D) Fuse |
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| 359. |
The connection of serial sets that are used in marriages A) Parallel B) Series C) Parallel, Series D) Series, Parallel |
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Answer» Correct option is B) Series |
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| 360. |
How does the brightness of the bulb change when a number of bulbs are connected in i) series ii) parallel? |
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Answer» i) If a number of bulbs are connected in series the brightness of the bulb is reduced. ii) If the number of bulbs are connected in parallel, the brightness of the bulb remains same. |
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| 361. |
When a glass rod is rubbed with silk, itA. the glass rod acquires a positive charge due to loss of electrons.B. the silk cloth acquires negative charge due to gain of electrons.C. if these two bodies are again brought in contact the net charge on them is zero.D. All the above. |
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Answer» Correct Answer - D We know that, a body which loses electrons acquires a positive charge and a body which gains electrons acquires a negative charge. And when these two charged bodies are brought in contact again, the net charge will be zero,due to neutralization of charge. |
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| 362. |
`"______"` is a major component of an electric bell. |
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Answer» Correct Answer - an electromagnet An electromagnet is a major component of an elec-tric bell. |
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| 363. |
Give reason:When a glass rod is rubbed with silk cloth, both get charged. |
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Answer» When a glass rod is rubbed with a silk cloth the free electrons in the glass rod are transferred to silk cloth. It is because the free electrons in the glass rod are less tightly bound as compared to that in silk cloth. Since the glass rod looses electrons, it has a deficiency of electrons and hence acquires positive charge. But, the silk cloth has excess of electrons. So, it becomes negatively charged. |
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| 364. |
What will be the charges on silk and glass rod when they are rubbed against each other? |
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Answer» 1. When a glass rod is rubbed with silk piece, the free electrons in the glass rod are transferred to silk piece. 2. It is because the free electrons in the glass rod are tightly bound as compared to that in silk piece. 3. Since the glass rod looses electrons, it has a deficiency of electrons and hence acquires positive charge. 4. But, silk piece has excess of electrons. 5. So, it becomes negatively charged. |
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| 365. |
Nichrome is the material used to make `"______"` elements. |
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Answer» Correct Answer - heating Nichrome is the material used to make heating elements. |
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| 366. |
A body can be charged byA. frictionB. inductionC. conductionD. All the above. |
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Answer» Correct Answer - D A body can be charged by friction, conduction and induction. |
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| 367. |
Write true or false for the statement:When a ebonite rod is rubbed with fur, the protons move from the ebonite rod to the fur. |
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Answer» False. Correct: When an ebonite rod is rubbed with fur, the free electrons move from the fur to the ebonite rod. |
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| 368. |
Electric iron, electric cooker contain a coil of wire made of A) nichrome B) zinc C) iron D) any one |
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Answer» Correct option is A) nichrome |
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| 369. |
When electric current passes through a wire, `"_______"` field is created around it. |
| Answer» Correct Answer - magnetic field | |
| 370. |
`"_______"` or `"_______"` is used to protect electrical appliances from damages due to excess current. |
| Answer» Correct Answer - fuse or miniature circuit breakers | |
| 371. |
Dry cell converts ………….. energy into electrical energy. A) potential B) chemical C) magnetic D) kinetic |
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Answer» Correct option is B) chemical |
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| 372. |
`"_______"` acts as a positive pole and `"_______"` as a negative pole in a dry cell. |
| Answer» Correct Answer - carbon rod, zinc can | |
| 373. |
Four cells of e.m.f. 2.5 V each are connected in series to form a battery, the e.m.f. of the battery is `"_______"`. |
| Answer» Correct Answer - 10 V | |
| 374. |
`"_______"` and `"_______"` are two defects of voltaic cell. |
| Answer» Correct Answer - polarization, local action | |
| 375. |
Identify the correct statement/s related to polarization in voltraic cell. (a) When current passes through the voltaic cell, zinc plate starts dissolving in the acid and pro-duces hydrogen bubbles. (b) These hydrogen bubbles accumulate on the cop-per plate and develop resistance to the flow of current.A. Only (A) is true.B. Only (B) is true.C. Both (A) and (B) true.D. Both (A) and (B) are false. |
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Answer» Correct Answer - C When current passes through the voltaic cell, zic plate starts dissolving in the acid and products hydro-gen bubbles and these hydrogen bubbles accumulate on the copper plate and develop resistance to the flow of current. |
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| 376. |
We generally use a device in an electrical circuit, which is essential for safety of appliance as well as life. (i) What is that safety device called ? (ii) How it works and helps us to live happily ? (iii) Do you think it is necessary for every place where electricity is used ? |
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Answer» (i) Fuse (ii) Yes, Fuse protects circuit and appliances by stopping the flow of any unduly high electric current. (iii) Yes Associated Value: The learners will be able to understand and appreciate the importance of electric fuse in the domestic circuit. |
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| 377. |
A negatively charged body is connected to the ground, then choose the correct statement. (A) Electrons flow from bodyto ground. (B) It becomes positively charged.A. Only A is trueB. Only B is trueC. Both A and B are trueD. Both A and B are false |
| Answer» Correct Answer - A | |
| 378. |
`"_____"` is a safety device that prevents excess flow of current through an appliance. |
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Answer» Correct Answer - fuse Fuse is a safety device that prevents excess flow of current through an appliance. |
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| 379. |
A current carrying conductor produces `"______"`A. only featB. only megnetic fieldC. Both heat and magnetic fieldD. None of the above |
| Answer» Correct Answer - C | |
| 380. |
An electric motor convertsA. electrical energy into mechanical energy.B. mechanial energy into electrical energy.C. heat energy into electrical energy.D. None of the above |
| Answer» Correct Answer - A | |
| 381. |
Mercury coated on zinc plate prevents the impuri-ties from coming into contact with acid and prevents `"______"`. |
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Answer» Correct Answer - local action Mercury coated on zinc plate prevents the impurities from conming into contact with acid and prevents local action. |
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| 382. |
ELECTRIC FUSE - A SAFETY DEVICE |
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Answer» Correct Answer - fuse Fuse is a safety device that prevents excess flow of current through an appliance. |
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| 383. |
1 unit of power equal to A) 1MW B) 1MWH C) 1KW D) 1KWH |
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Answer» Correct option is D) 1KWH |
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| 384. |
Inside a cell, the conventional current flows from the _______ terminal to the __________ terminal. |
| Answer» Correct Answer - Negative, positive. | |
| 385. |
A force of `45 xx 10^(-3) N` acts between two like charge bodies separated by 4 m in the air. If the magnitude of one of charges is `8 muC`, find the magnitude of the other charge. |
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Answer» Given `q_(1) = 8 muC = 8 xx 10^(-6)C` Distance between two charges, `(r ) = 4 m` Electrostatic force of repulsion , `(F) = 45 xx 10^(-3) N` `1/(4piepsi_(0)) = 9 xx 10^(9) N m^(2)C^(-2)` `q_(2) = ?` `F = 1/(4 pi epsi_(0)) (q_(1)q_(2))/(r^(2))` `:. 45 xx 10^(-3) = 9 xx 10^(9) xx (8 xx 10^(-6) xx q_(2))/((4)^(2)) = rArr q_(2) = 10 muC` |
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| 386. |
Write the following steps in sequential order to prove that like charges rapel each other. (A) Take two galss rods. (B) Now bring these two charged rods nearer. (B) Now bring these two charged rods nearer. (C) Charge them by rubbing each glass rod with a silk cloth. (D) The glass rods equal other showing that like charges repel each other.A. ABCDB. ACBDC. DCBAD. BDAC |
| Answer» Correct Answer - B | |
| 387. |
Write true or false for the statement:A conductor has a large number of free electrons. |
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Answer» A conductor has a large number of free electrons. True |
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| 388. |
Match the following:Column AColumn B(a) Two like charges(i) negative charge(b) Two unlike charge(ii) repel(c) Silver is a(iii) insulator(d) Silk is an(iv) attract(e) Ebonite rod rubbed with fur acquires(v) conductor |
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Answer»
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| 389. |
When a conductor is connected to a source of current, the number of electrons entering at one end of the conductor is equal to the number of electrons leaving the conductor from the other end, per second |
| Answer» Correct Answer - 1 | |
| 390. |
`n` electrons flow through a cross-section of a conductor in time `t`. If the charge on an electron is `e`, write an expression for the current in the conductor. |
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Answer» Correct Answer - ne//t `I = (Q)/(t) = ("ne")/(t)`. |
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| 391. |
Electrons are responsible for conduction in a conductor. The speed of electron is not very high. Then, how the bulb is on immediately even through the switch and bulb are far away from each other in a household circuit? |
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Answer» This is because the number of the free electrons constituting current in a typical conductor is very large of order 1018 or more. This large electron number density keeps the good amount of current flowing through. |
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| 392. |
Write true or false for the statement:A lightning conductor saves the building from lighting. |
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Answer» A lightning conductor saves the building from lighting. True |
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| 393. |
Write true or false for the statement:In induction, a positively charged body can make an uncharged ‘ body positively charged. |
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Answer» False Correct: In induction, a positively charged body can make an uncharged body negatively charged. |
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| 394. |
(a) Write two points of difference between electric energy and electric power. (b) Out of 60 W and 40 W lamps, which one has higher electrical resistance when in use. (c) What is the commercial unit of electric energy? Convert it into joules. |
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Answer» (a) Difference between electric energy and electric power:
(b) less the power of electrical device, higher is its electrical resistance. (c) Kilowatt hour – Commercial unit of electrical energy 1 kWh = 1000 Wh = 1000 J/S x 3600 sec = 3600000 J = 3.6 x106 J |
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| 395. |
Describe the electrostatic force that exists between A and B in the following cases. |
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Answer» (a) Both A and B are netural , hence, no electrostatic force. (b) and (c ) As one of them is charged there exists an attractive force due to introduction. (d) As A and B are oppositely charged, there exists an attractive force between them. (e) and (f) As A and B are identically charged, there exists a repulsive froce between them. |
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| 396. |
How is direction of current related to the direction of flow of electrons? |
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Answer» The direction of current is opposite to the direction of flow of electrons. |
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| 397. |
(a) How is the direction of electric current related to the direction of flow of electrons in a wire? (b) Calculate the current in a circuit if 500 C of charge passes through it in 10 minutes. |
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Answer» (a) Conventional direction of electric current is opposite to the direction of flow of electrons in a wire. (b) q = 500 C, t = 10 X 60 = 600 s I = 500/600 = 5/6A |
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| 398. |
Assertion and Reason.Assertion (A) : Copper1 is used to make electric wires. Reason (R) : Copper has very low electrical resistance.Option:A. Both A and R are true and R is the correct explanation of A. B. Both A and R are true but R is NOT the correct explanation of A. C. A is true but R is false. D . A is false but R is true. E. Both A and R are false . |
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Answer» A. Both A and R are true and R is the correct explanation of A |
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| 399. |
Assertion (A) : Insulators do not allow the flow of current through themselves. Reason (R) : They have no free charge carriers. A. If both A and R are true and the R is correct explanation of A. B. If both A and R are true but R is not a correct explanation of A. C. If A is true and R is false. D. If both A and R are false |
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Answer» A. If both A and R are true and the R is correct explanation of A |
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| 400. |
Assertion and Reason.Assertion (A) : Insulators do not allow flow of current through them. Reason (R) : Insulators have no free charge carrierMark the correct choice as (a) Both A and R are true but R is the correct explanation of assertion.(b) Both A and R are true but R is not correct explanation of assertion.(c) A is true but R is false.(d) A is false but R is true. |
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Answer» (a) Both A and R are true but R is the correct explanation of A |
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