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Ask questions which are clear, concise and easy to understand.

How the rate of flux change
Posted by Sachin Negi (Aug 19, 2017 5:52 p.m.) (Question ID: 13581)

• the emf (electric potential) induced in the coil is proportional to the rate of change of flux linkage. In practice, this means that if the coil is stationary relative to the magnetic field, no emf is induced. In order to induce emf, either the coil or the magnetic field must move.

Answered by Sahdev Sharma (Aug 19, 2017 5:56 p.m.)
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While deriving the expression for motional emf ,dx/dt has taken as -v.Why -v not as only v?
Posted by Swati Singh (Aug 19, 2017 5:12 p.m.) (Question ID: 13560)

1 mole of an ideal gas is taken through a cyclic process. The minimum temperature during the cycle is 300K. Then net exchange of heat for complete cycle is
Posted by Ritu Jha (Aug 19, 2017 4:16 p.m.) (Question ID: 13523)

What is inductance?
Posted by Swati Singh (Aug 19, 2017 3:22 p.m.) (Question ID: 13487)

• Yes it is correct
Posted by Swati Singh (Aug 19, 2017 4:41 p.m.)
• It is the property of electric coductor due to which a change in current through it induces an emf in itself & nearby of any other conductor by the process called mutual inductance..I think it is correct??
Answered by Sahana Roy (Aug 19, 2017 3:36 p.m.)
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Hc Verma pg 167 qs. 25(d)[chap-capacitors]
Posted by Hhhh P (Aug 19, 2017 2:05 p.m.) (Question ID: 13442)

• First complete ur ncert!!
Posted by Swati Singh (Aug 19, 2017 3:17 p.m.)
What is intensity
Posted by Shashi Kant (Aug 19, 2017 1:40 p.m.) (Question ID: 13430)

What is polarisation of cell??
Posted by Sahana Roy (Aug 19, 2017 1:16 p.m.) (Question ID: 13422)

what is electrostatic
Posted by Pratyushaa Maun (Aug 19, 2017 12:55 p.m.) (Question ID: 13417)

• Electrostatics is a branch of physics that deals with study of the electric charges at rest. Since classical physics, it has been known that some materials such as amber attract lightweight particles after rubbing.

Answered by Sahdev Sharma (Aug 19, 2017 12:57 p.m.)
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Is it possible to for a metallic sphere of radius 1 cm to hold a charge of 1 coulomb??plz help..
Posted by Sahana Roy (Aug 19, 2017 12:55 p.m.) (Question ID: 13416)

What is the range of electromagnetic wave
Posted by Ram Ray (Aug 19, 2017 12:46 p.m.) (Question ID: 13414)

• It has clearly specified in ncert.
Posted by Swati Singh (Aug 19, 2017 3:24 p.m.)
What is density
Posted by Dhnanjay Uoadhyay (Aug 19, 2017 12:07 p.m.) (Question ID: 13395)

• Density is a characteristic property of a substance.
• The density of a substance is the relationship between the mass of the substance and how much space it takes up (volume).
• The mass of atoms, their size, and how they are arranged determine the density of a substance.
• Density equals the mass of the substance divided by its volume; D = m/v.
Answered by Sahdev Sharma (Aug 19, 2017 12:09 p.m.)
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what is AC-DC current
Posted by Beena Choudhary (Aug 19, 2017 5:56 a.m.) (Question ID: 13269)

A bird sitting on a high tension wire does not get electric shock.why?
Posted by Anjali Maheshwari (Aug 18, 2017 10:53 p.m.) (Question ID: 13219)

• The bird does not get an electric shock because the potential difference is zero . until the bird will not come in contact with another conductor it is safe.
Answered by Pragya Dhandore (Aug 18, 2017 11:02 p.m.)
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Define capacitor
Posted by Aditya Tiwari (Aug 18, 2017 8:43 p.m.) (Question ID: 13082)

• Capacitor is a device which store current. Capacitor & condenser both are same
Posted by Anshul Singh (Aug 18, 2017 9:12 p.m.)
• Which can store energy and remove also but capacitor should not be confused with battery.
Answered by Sneha Tiwari (Aug 18, 2017 8:56 p.m.)
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How much marks do optics hold
Posted by Shivansh Bhagat (Aug 18, 2017 8:38 p.m.) (Question ID: 13074)

• Ray optics + wave optics + EM waves collectively 15 marks
Posted by Prateek Malviya (Aug 18, 2017 9:42 p.m.)
Define lenz's law ????
Posted by Ravi Gandass (Aug 18, 2017 8:33 p.m.) (Question ID: 13064)

• Mae fb par hu at Ravi Singh
Posted by Ravi Gandass (Aug 19, 2017 9:30 a.m.)
• The oxymercuration reaction is an electrophilic addition organic reaction that transforms an alkene into a neutral alcohol. Oxymercuration followed by reductive demercuration is called an oxymercuration–reduction reaction or oxymercuration–demercuration reaction. This reaction, which is almost always done in practice instead of oxymercuration, is treated at the conclusion of the article.
Posted by Ravi Gandass (Aug 19, 2017 9:29 a.m.)
• Can you tell me something about oxymercuration and demercuration reaction?
Posted by Pragya Dhandore (Aug 18, 2017 10:44 p.m.)
• Lenz's law states that the direction of an induced current is always such as to oppose the change in the circuit or the magnetic field that produces it .
Answered by Pragya Dhandore (Aug 18, 2017 9:41 p.m.)
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Discuss about Lenz's law in accordance with Law of conservation of energy?
Posted by Sahil Jaat (Aug 18, 2017 8:25 p.m.) (Question ID: 13047)

• According to Lenz's law " Change in mag flux always opposes the cause which is producing it. So to change the mag. flux we have to do mechanical work i.e mechanical energy gets converted into electrical energy. So lenz's law is in accordance with law of conservation of energy.
Answered by Saurav Chamoli (Aug 19, 2017 6:02 a.m.)
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Derivation of ohm law
Posted by Suyash Dwivedi (Aug 18, 2017 8:17 p.m.) (Question ID: 13034)

A choke coil and a bulb are connected in series to a d.c source. Bulb shines brightly.how does the brightness changes when an iron core is inserted in the choke coil
Posted by Mahek Desai (Aug 18, 2017 8:02 p.m.) (Question ID: 13012)

A variable frequency 230V A C source is connected across a series combination of inductance 5H , capacitance80microferade and resistance 5ohm 1- find agular frequency of source which derives the circuit resonance 2 -impidence of circuit and amplitude of current at resonance 3-rms potential drop across the three elements of the circuit showing that the potential difference across the LC combination is zero
Posted by Jasdeep Singh Dhillon (Aug 18, 2017 7:36 p.m.) (Question ID: 12967)

What is potential
Posted by Shiv Chouhan (Aug 18, 2017 6:51 p.m.) (Question ID: 12909)

• It is the amount of work done in moving a unit positive charge from one point to another point in an electric field.

Answered by Arun Soni (Aug 18, 2017 7:08 p.m.)
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What is a static charge
Posted by Amit Jangir (Aug 18, 2017 6:38 p.m.) (Question ID: 12894)

• Static electricity is an imbalance of electric charges within or on the surface of a material. The charge remains until it is able to move away by means of an electric current or electrical discharge. Static electricity is named in contrast with current electricity, which flows through wires or other conductors and transmits energy

Answered by Himanshu Singhal (Aug 18, 2017 7:05 p.m.)
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What is the weightage of numericals in physics board exam??
Posted by Sri Sharma (Aug 18, 2017 5:11 p.m.) (Question ID: 12831)

• 16 to 18 Marks
Posted by Murtaja Ali Pitolwala (Aug 18, 2017 7:02 p.m.)
Which one would have higher resistance ammeter or multimeter when connected to a galvanometer
Posted by Sri Sharma (Aug 18, 2017 5:06 p.m.) (Question ID: 12828)

Do van de graff generator comes in borad examination?? I mean is it the topic pf class 12 sllaybus
Posted by Mohit Pawar (Aug 18, 2017 4:47 p.m.) (Question ID: 12818)

• No
Posted by Swati Singh (Aug 18, 2017 7:25 p.m.)
Calculate resistivity when 5% of of metao
Posted by Hritik Kumar (Aug 18, 2017 2:59 p.m.) (Question ID: 12772)

Describe lcr circuit
Posted by Rashmi Mishra (Aug 18, 2017 2:44 p.m.) (Question ID: 12762)

Flux changes in ac or DC current and why?
Posted by A E (Aug 18, 2017 7:03 a.m.) (Question ID: 12657)

What is the distance between nucleus and electron in a hydrogen atom?
Posted by Sahil Jaat (Aug 18, 2017 6:38 a.m.) (Question ID: 12648)

• The Bohr radius (a0 or rBohr) is a physical constant, approximately equal to the most probable distance between the center of a nuclide and the electron in a hydrogen atom in its ground state. It is named after Niels Bohr, due to its role in the Bohr model of an atom. Its value is 5.2917721067 x 10−11 m.

Answered by Himanshu Singhal (Aug 18, 2017 7:08 a.m.)
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Why Silicon is preferred as best semiconductor in carbon family?
Posted by Nikhil Chaturvedi (Aug 17, 2017 11:34 p.m.) (Question ID: 12601)

• Silicon atoms have four electrons which can be shared in covalent bonds with neighboring atoms. Silicon is the principal component of common sand, and for this reason it is less expensive than other intrinsic semiconductor materials.

Answered by Arun Soni (Aug 18, 2017 3:56 a.m.)
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