Skip to main content

Direct Current Short Questions

           1.   Why do we use connecting wires made of copper?
2.      A wire carrying current remains electrically neutral. Why?
3.      A large number of free electrons are present in metals. Why is there no current in the absence of electric field across it?
4.      Why do electrons acquire a steady drift velocity after applying a voltage?
5.      A wire of resistivity ρ is stretched to three times its length. What will be its new resistivity?
6.      Name any two physical parameters on which the resistivity of the material depends?
7.      Manganin and constantans are used for making standard resistors. Why?
8.      Two wires of equal length, one of copper and other manganin, have equal resistance. Which wire is thicker?
9.      Why is it dangerous to operate electrical appliances with wet hands?
10.   What is the effect of heating a conductor on the drift velocity of free electrons?
11.   Is it possible to make the resistance of metals equal to zero by any way?
12.   If the radius of wire is doubled, what will be the effect on its specific resistance?
13.   What is the effect of rise in temperature on the resistivity of semiconductor?
14.   State the condition on which the ohm's law is not obeyed in a conductor?
15.   Why are electrons not accelerated indefinitely in a conductor when electric potential difference is set up across its ends?
16.   On what factor does the resistance of a conductor depends on?
17.   A wire is stretched to double its length, what happens to its resistance and resistivity?
18.   Distinguish between ohmic and non-ohmic conductors?
19.   How do the resistance and resistivity of a conductor vary with temperature?
20.   Current density is a vector quantity, but current is a scalar quantity. Explain?
21.   The element of a heater is very hot while the wires carrying current are cold. Why?
22.   Explain why a bending of wire does not affect the value of drift speed of free electrons and hence the current?
23.   Although the drift velocity of free electrons is of the order of few mm/s, a bulb lights almost instantly. Why?
24.   A cylindrical rod has resistance R. If we double its length and diameter, what is the resistance in terms of R?
25.   Two copper wires of different diameter are joined end to end. If a current flows in the wire combination, what happens to the drift velocity of the electrons when they are moved from the larger diameter of the wire to smaller diameter wire?
26.  Why does an electric bulb nearly always burn out just as we turn on the light, but almost never while light is shining?
27.   Is there any difference between "resistance of wire" and "resistivity of wire"? Explain.
28.   What is the ratio of maximum to minimum resistance obtainable from n wires of resistance R each?
29.   Why is voltmeter connected in parallel with the load resistance?
30.   Why ammeter is connected in series?
31.   Explain the significant of shunt with a diagram?
32.   The electron drift speed in metals is small and the charge of electron is also very small, but we can still obtain a large amount of current in a metal. Why?
33.   When electrons drift in a metal from a lower potential to higher potential, all the free electrons of  the metals move in the same direction. Is this statement true? Explain.
34.    Is the ohm's law applicable to all conductors of electricity?
35.   A proton beam is going from east to west. Is there an electric current? If yes, in what direction?
36.   Explain how do you know whether two resistances in a circuit are connected in parallel or in series?
37.   What is the main difference between voltmeter and ammeter?
38.   How are lamps connected in a house? How is the fuse connected?
39.   Which of the quantities current, current density, electric field and drift speed remains constant along a non uniform conductor when a current is passed?
40.   What happens when ammeter connected in parallel and voltmeter connected in series in the circuit?
41.   Does the value of temperature coefficient of resistance always positive?
42.   By connecting suitable resistance in series, two identical galvanometers are converted into voltmeter and milli-voltmeter, which has higher resistance?
43.  Why don't we consider a drift velocity of positive ions?
44.   What are the factors on which the resistance of conductor depend?
45.   Alloys of metals have greater resistivity than that of their constituent metals? Why?
46.  What is the difference between static electricity and current electricity.
47.  Currents of the order of 0.1A through human body are fatal what causes death: heating due to current o something else?
48.  If electron drift speed is small, and the charge on electron is also very small, how can we obtain large amount of current in the conductor?
49.  There is an impression among people that person touching a high power line gets stuck with it. Is that true? Explain.
50.  A wire is carrying current. Is it charged?


Popular posts from this blog

Characteristics of good tax system. (Canons of taxation)

Tax is an effective fiscal tool to influence the economy. It has also certain norms which have to be followed to make it more effective and popular. That state is a welfare state which imposes less amount of tax and collects more amount of revenue. So the tax should be effective. A good tax system should help to establish fair income distribution and socio-economic stability. According to Adam Smith, "A tax is a contribution from citizens for the support of the state." Adam Smith has given the most comprehensive and exhaustive concept of a good tax system which is known as the canon of taxation.  1 Canon of equity  A good tax should be based on the ability to pay principle of taxation, and it has to assure social justice to all taxpayers. In general, in this canon of equity, everybody must be treated equally for tax or according to capacity or ability they should pay the tax and unequal must be treated unequally....
Read more

Teej : The Most Awaited Festival for Nepalese Women

Written By: Jaya Silwal Red, green and yellow, these are the only colors that can be seen everywhere; mostly dominated by the color red. Teej is the name of a red insect that comes out on the surface during the rainy season. The festival is said to have got its name from that very insect. That must be the reason why the whole town seems to be painted red that day. Metaphorically, you can see all the women and girls of all age groups on the streets enjoying the festival that it's not less than painting the town red. To those who don't have any idea, Haritalika Teej is one of the most-awaited and celebrated festivals of Hindu women in Nepal. This festival mostly falls on the 3rd day of Bhadra Shukla Pakshya according to the Nepali Lunar Calendar. It is a three-day-long celebration with the aim to increase the happiness, peace, prosperity, family harmony and the long life span of women's husbands or beloved. Traditionally, this festival is dedicated to Go...
Read more

Concept, meaning and function of Money

Concept and meaning of Money In general money simply refers to the currencies (notes, coins), produced by central bank of the nation. But in subject of monetary economics and financial and public economics, the concept of money isn’t this simple. Many arguments or views are given by different economists regarding the money. We considered here definition by some of the authors "In order for anything to be classed as money, it must be accepted fairly widely as an instrument of exchange." -  A C Pigou. "Money is anything that is habitually and widely used as means of payment and is generally acceptable in the settlement of debts." - G D H Cole. "Money constitutes all those things which are at any time and place, generally current without doubt or special enquiry as a means of purchasing commodities and services and of defraying expenses." - Alfred Marshal By money is to be understood "that by delivery of which debt contracts and price c...
Read more