English
Maharashtra State BoardSSC (English Medium) 10th Standard

Name the following diagram and explain the concept behind it.

Advertisements
Advertisements

Question

Name the following diagram and explain the concept behind it.

Explain
Advertisements

Solution

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.

shaalaa.com
  Is there an error in this question or solution?
Chapter 4: Effects of electric current - Exercises [Page 61]

RELATED QUESTIONS

State Fleming’s right-hand rule.


Explain different ways to induce current in a coil.


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?


A line charge λ per unit length is lodged uniformly onto the rim of a wheel of mass M and radius R. The wheel has light non-conducting spokes and is free to rotate without friction about its axis (Figure). A uniform magnetic field extends over a circular region within the rim. It is given by,

B = − B0 k (r ≤ a; a < R)

= 0 (otherwise)

What is the angular velocity of the wheel after the field is suddenly switched off?


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


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?


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 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.


Show diagrammatically how an alternating emf is generated by a loop of wire rotating in a magnetic field. Write the expression for the instantaneous value of the emf induced in the rotating loop.


The coil of a moving-coil galvanometer keeps on oscillating for a long time if it is deflected and released. If the ends of the coil are connected together, the oscillation stops at once. Explain.


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.


Figure shows a wire sliding on two parallel, conducting rails placed at a separation l. A magnetic field B exists in a direction perpendicular to the plane of the rails. What force is necessary to keep the wire moving at a constant velocity v?


The following diagram shows a fixed coil of several turns connected to a center zero galvanometer G and a magnet NS which can move in the direction shown in the diagram.

  1. Describe the observation in the galvanometer if
    1. The magnet is moved rapidly,
    2. The magnet is kept still after it has moved into the coil
    3. The magnet is then rapidly pulled out the coil.
  2. How would the observation in (i) of part (a) change if a more powerful magnet is used?


Draw and label the diagram of a simple D.C. motor.
(a) Explain the rotation of the coil, giving a reason for your answer.
(b) How can you reverse the direction of rotation of the armature?
(c) How can you increase the speed of rotation of the motor?


Fig. shows a simple form of an A.C. generator.

(a) Name the parts labeled A and B.
(b) What would be the effect of doubling the number of turns on the coil if the speed of rotation remains unchanged?
(c) Which of the output terminals is positive if the coil is rotating in the
direction shown in the diagram (anticlockwise)?
( d ) What is the position of the rotating coil when p.d. across its ends is zero? Explain why p.d. is zero when the coil is at this position .
(e) Sketch a graph showing how the p.d. across the ends of the rotating coil varies with time for an A.C. dynamo.
( f) On th e same sheet of paper and vertically below the first graph using the same time scale, sketch graphs to show the effect of
(i) Doubling the speed of rotation and at the same time keeping
the field and the number of turns constant,
(ii ) Doubling the number of turns on the coil and at the same time
doubling the speed of rotation of the coil, keeping th e speed
constant.


Fill in the blanks by writing (i) Only soft iron, (ii) Only steel, (iii) Both soft-iron and steel for the material of core and/or magnet.

Transformer______.


State Fleming’s Right Hand Rule.


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


List some of the practical applications of an electromagnet.


What is an electromagnet? What do you know about the simplest form of an electromagnet?


Draw a labelled diagram to make an electromagnet from a soft iron bar. Mark the polarity at its ends in your diagram. What precaution would you observe while making it?


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.


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. 


Observe the given figure of Fleming’s Right Hand Rule and write the labels of A and B correctly.


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 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.


The laws of electromagnetic induction have been used in the construction of a ______.

The instrument that use to defect electric current in the circuit is known as ____________.


Induced current flows through a coil ______.


Which of the following instruments works by electromagnetic induction?


For making a strong electromagnet the material of the core should be ______.


A rectangular, a square, a circular and an elliptical loop, all in the (x - y) plane, are moving out of a uniform magnetic field with a constant velocity `vecv = vhati`. The magnetic field is directed along the negative z-axis direction. The induced emf, during the passage of these loops, out of the field region, will not remain constant for ______.


In the current carrying conductor (AOCDEFG) as shown, the magnetic induction at point O is ______.

(R1 and R2 are radii of CD and EF respectively. l = current in the loop, μ0 = permeability of free space)

 


Share
Notifications

Englishहिंदीमराठी


      Forgot password?
Use app×