मराठी
महाराष्ट्र राज्य शिक्षण मंडळएस.एस.सी (इंग्रजी माध्यम) इयत्ता १० वी

Name the following diagram and explain the concept behind it.

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प्रश्न

Name the following diagram and explain the concept behind it.

स्पष्ट करा
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उत्तर

Name: Fleming’s right-hand rule

Concept: It represents Fleming’s right-hand rule used for finding the direction of the induced current with respect to the directions of the magnetic field and motion of the conductor.

The direction of the current induced in a conductor can be obtained by holding the thumb, the index finger, and the middle finger of your right hand mutually perpendicular to each other. In this situation, the thumb indicates the direction of the motion of the conductor, the index finger points along the magnetic field, and the middle finger points along the current induced in the conductor.

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पाठ 4: Effects of electric current - Exercises [पृष्ठ ६१]

संबंधित प्रश्‍न

Electric field intensity in free space at a distance ‘r’ outside the charged conducting sphere of radius ‘R’ in terms of surface charge density ‘ a ’ is............................

(a)`sigma / in_0[R/r]^2`

(b)`in_0/sigma[R/r]^2`

(c)`R/r[sigma/in_0]^2`

(d)`R/sigma[r/in_0]^2`

 


The magnetic flux through a loop is varying according to a relation `phi = 6t^2 + 7t + 1` where `phi` is in milliweber and t is in second. What is the e.m.f. induced in the loop at t = 2 second?


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.


When an electric current is passed through any wire, a magnetic field is produced around it. Then why an electric iron connecting cable does not attract nearby iron objects when electric  current switched on through it?


The north-south polarities of an electromagnet can be found easily by using:

(a) Fleming's right-hand rule
(b) Fleming's left-hand rule
(c) Clock face rule
(d) Left-hand thumb rule


When a wire is moved up and down in a magnetic field, a current is induced in the wire. What is this phenomenon known as?


When current is 'switched on' and 'switched off' in a coil, a current is induced in another coil kept near it. What is this phenomenon known as?


 What do you understand by the term "electromagnetic induction"? Explain with the help of a diagram. 


An induced current is produced when a magnet is moved into a coil. The magnitude of induced current does not depend on:  

(a) the speed with which the magnet is moved
(b) the number of turns of the coil
(c) the resistivity of the wire of the coil
(d) the strength of the magnet


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.


  1. What kind of energy change takes place when a magnet is moved towards a coil having a galvanometer at its ends?
  2. Name the phenomenon.

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

A loop of wire is held near a magnet.


Welders wear special glass goggles while working. Why? Explain.


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.


Electromagnetic induction means ______.


 Can a transformer work when it is connected to a D.C. source? Give a reason.


Draw a simple labeled diagram of a step-down transformer.


Draw a simple labeled diagram of a step-up transformer.


A transformer has 400 turns in the primary winding and 10 turns in the secondary winding. The primary e.m.f. is 250 V and the primary current is 2.0 A. calculate:
(a) The secondary voltage,
(b) The secondary current, assuming 100% efficiency.


A coil has a self-inductance of 0·05 Henry. Find the magnitude of the emf induced in it when the current flowing through it is changing at the rate of 100 As-1.


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


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


You have been provided with a solenoid AB.

(i) What is the polarity at end A?
(ii) Give one advantage of an electromagnet over a permanent magnet.


Write the two names in the following diagram.

Right hand thumb rule.


State Fleming’s right-hand rule.


A square coil of side 30 cm with 500 turns is kept in a uniform magnetic field of 0.4 T. The plane of the coil is inclined at an angle of 30° to the field. Calculate the magnetic flux through the coil.


A closely wound circular coil of radius 0.02 m is placed perpendicular to the magnetic field. When the magnetic field is changed from 8000 T to 2000 T in 6 s, an emf of 44 V is induced in it. Calculate the number of turns in the coil.


Shown in the figure below is a metre bridge set up with null deflection in the galvanometer. The value of the unknown resistance R is ______

     


Metal rings P and Q are lying in the same plane, where current I is increasing steadily. The induced current in metal rings is shown correctly in figure.


A layer of atmosphere that reflects medium frequency radio waves which is ineffective during night, is ______.


A cylindrical bar magnet (A) and similar unmagnetized cylindrical iron bar (B) are dropped through metallic pipe. The time taken to come down by ____________.


A generator has an e.m.f. of 440 Volt and internal resistance of 4000 hm. Its terminals are connected to a load of 4000 ohm. The voltage across the load is ______.


Which of the following instruments works by electromagnetic induction?


A galvanometer is an instrument that can detect the presence of a current in a circuit.


AB is a coil of copper wire having a large number of turns. The ends of the coil are connected with a galvanometer as shown. When the north pole of a strong bar magnet is moved towards end B of the coil, a deflection is observed in the galvanometer.

  1. State the reason for using galvanometer in the activity and why does its needle deflects momentarily when magnet is moved towards the coil.
  2. What would be observed in the galvanometer in a situation when the coil and the bar magnet both move with the same speed in the same direction? Justify your answer.
  3. State the conclusion that can be drawn from this activity.
    Will there be any change in the momentary deflection in the galvanometer if number of turns in the coil is increased and a more stronger magnet is moved towards the coil?

OR

What is electromagnetic induction? What is observed in the galvanometer when a strong bar magnet is held stationary near one end of a coil of large number of turns? Justify your answer.


An expression for oscillating electric field in a plane electromagnetic wave is given as Ez = 300 sin(5π × 103x - 3π × 1011t)Vm-1 Then, the value of magnetic field amplitude will be ______. (Given: speed of light in Vacuum c = 3 × 108 ms-1)


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