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महाराष्ट्र राज्य शिक्षण मंडळएचएससी विज्ञान (सामान्य) इयत्ता १२ वी

The energy stored in a 50 mH inductor carrying a current of 4 A is ______ - Physics

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प्रश्न

The energy stored in a 50 mH inductor carrying a current of 4 A is ______ 

पर्याय

  • 0.4 J

  • 0.1 J

  • 0.04 J

  • 0.01 J

MCQ
रिकाम्या जागा भरा

उत्तर

The energy stored in a 50 mH inductor carrying a current of 4 A is 0.4 J.

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पाठ 12: Electromagnetic Induction - MCQ’S

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संबंधित प्रश्‍न

The magnetic flux through a loop varies according to the relation Φ = 8t2 + 6t + C, where ‘C’ is constant, 'Φ' is in milliweber and 't' is in second. What is the magnitude of induced e.m.f. in the loop at t = 2 seconds.


State Fleming’s right-hand rule.


A metal rod `1/sqrtpi `m long rotates about one of its ends perpendicular to a plane whose magnetic induction is 4 x 10-3 T. Calculate the number of revolutions made by the rod per second if the e.m.f. induced between the ends of the rod is 16 mV.


When a bar magnet is pushed towards (or away) from the coil connected to a galvanometer, the pointer in the galvanometer deflects. Identify the phenomenon causing this deflection and write the factors on which the amount and direction of the deflection depends. State the laws describing this phenomenon.


 Two circular coils A and B are placed closed to each other. If the current in the coil A is changed, will some current be induced in the coil B? Give reason.


A rectangular wire loop of sides 8 cm and 2 cm with a small cut is moving out of a region of uniform magnetic field of magnitude 0.3 T directed normal to the loop. What is the emf developed across the cut if the velocity of the loop is 1 cm s−1 in a direction normal to the

  1. longer side,
  2. shorter side of the loop? 

For how long does the induced voltage last in each case?


Prove theoretically  (electromagnetic induction) `e = (dphi)/(dt)`


If ‘R’ is the radius of dees and ‘B’ be the magnetic field of induction in which positive charges (q) of mass (m) escape from the cyclotron, then its maximum speed (vmax) is _______.

A) `(qR)/(Bm)`

B)`(qm)/(Br)`

C) `(qBR)/m`

D) `m/(qBR)`


An emf of 2V is induced in a coil when the current in it is changed from 0A to 10A in 0·40 sec. Find the coefficient of self-inductance of the coil.


 How does an electromagnet differ forma permanent magnet?  

 


 Name two devices in which electromagnets are used and two devices where permanent magnets are used.


What is an electromagnet? Describe the construction and working of an electromagnet with the help of a labelled diagram.


 State the factors on which the strength of an electromagnet depends. How does it depend on these factors?


Write some of the important uses of electromagnets. 


The most suitable material for making the core of an electromagnet is:

(a) soft iron
(b) brass
(c) aluminium
(d) steel


What condition is necessary for the production of current by electromagnetic induction?


State whether the following statement are true or false: 

 A generator works on the principle of electromagnetic induction. 


When the magnet shown in the diagram below is moving towards the coil, the galvanometer gives a reading to the right. 

 

() What is the name of the effect being produced by the moving magnet?
(2) State what happens to the reading shown on the galvanometer when the magnet is moving away from the coil.
(3) The original experiment is repeated. This time the magnet is moved towards the coil at a great speed. State two changes you would notice in the reading on the galvanometer.


In which of the following case does the electromagnetic induction occur?

A magnet is moved through a loop of wire .


When Puja, a student of 10th class, watched her mother washing clothes in the open, she observed coloured soap bubbles and was curious to know why the soap bubbles appear coloured. In the evening when her father, an engineer by profession, came home, she asked him this question. Her father explained to her the basic phenomenon of physics due to which the soap bubbles appear coloured.
(a) What according to you are the values displayed by Puja and her father?
(b) State the phenomenon of light involved in the formation of coloured soap bubbles.


A light metal disc on the top of an electromagnet is thrown up as the current is switched on. Why? Give reason.


L, C and R represent the physical quantities inductance, capacitance and resistance respectively. Which of the following combinations have dimensions of frequency?

(a) `1/(RC)`

(b) `R/L`

(c) `1/sqrt(LC)`

(d) C/L


The switches in figure (a) and (b) are closed at t = 0 and reopened after a long time at t = t0.

(a) The charge on C just after t = 0 is εC.
(b) The charge on C long after t = 0 is εC.
(c) The current in L just before t = t0 is ε/R.
(d) The current in L long after t = t0 is ε/R.


Calculate the dimensions of (a) \[\int \overrightarrow{E} . d \overrightarrow{l,}\] (b) vBl and (c) \[\frac{d \Phi_B}{dt}.\] The symbols have their usual meaning.


A conducting square loop having edges of length 2.0 cm is rotated through 180° about a diagonal in 0.20 s. A magnetic field B exists in the region which is perpendicular to the loop in its initial position. If the average induced emf during the rotation is 20 mV, find the magnitude of the magnetic field.


Answer the following:

State the principles of the electric motor and electric generator. 


Draw a labelled diagram to show how an electromagnet is made.


State the purpose of soft iron core used in making an electromagnet.


Why soft iron is preferred to be used as the core of the electromagnet of an electric bell?


Choose the correct option:

A conductor rod of length (l) is moving with velocity (v) in a direction normal to a uniform magnetic field (B). What will be the magnitude of induced emf produced between the ends of the moving conductor?


State the condition at which we say the two coils kept close to each other are perfectly coupled with each other. 


Using Ampere's law, obtain an expression for the magnetic induction near a current-carrying straight infinitely long wire. 


Find the odd one out and give its explanation.


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Establish the fact that the relative motion between the coil and the magnet induces an emf in the coil of a closed circuit.


Show that Lenz’s law is in accordance with the law of conservation of energy.


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An induced current of 2.5 mA flows through a single conductor of resistance 100 Ω. Find out the rate at which the magnetic flux is cut by the conductor.


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A 50 cm long solenoid has 400 turns per cm. The diameter of the solenoid is 0.04 m. Find the magnetic flux linked with each turn when it carries a current of 1 A.


Using Lenz’s law, predict the direction of induced current in conducting rings 1 and 2 when the current in the wire is steadily decreasing.


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