मराठी

What Device Reverses the Current?

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प्रश्न

 What device reverses the current?

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उत्तर

 A commutator (split rings) reverses the current.

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पाठ 5: Magnetic Effects of Electric Current - Exercise 3 [पृष्ठ ९२]

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लखमीर सिंह Physics [English] Class 10
पाठ 5 Magnetic Effects of Electric Current
Exercise 3 | Q 20.2 | पृष्ठ ९२

व्हिडिओ ट्यूटोरियलVIEW ALL [2]

संबंधित प्रश्‍न

Do you think an electromagnet can be used for separating plastic bags from a garbage heap? Explain.


Which effect of current can be utilised in detecting a current carrying wire concealed in a wall? 


Name the scientist who discovered the magnetic effect of current.


For the coil in the diagram below, when the switch is pressed:

(a) what is the polarity of end A?
(b) which way will the compass point then?    


The direction of current flowing in the coil of an electromagnet at its two ends X and Y are as shown below:  

  

 What is the polarity of end X?

What is the polarity of end Y?   

Name and state the rule which you have used to determine the polarities. 


When the switch S is closed in the figure given below, the pointer of the galvanometer moves to the right.  

 

If S is kept closed, will the pointer:

(a) return to zero?
(b) stay over on the right?
(c) move to the left and stay there
(d) move to and fro until S is opened


The north pole of a long bar magnet was pushed slowly into a short solenoid connected to a galvanometer. The magnet was held stationary for a few seconds with the north pole in the middle of the solenoid and then withdrawn rapidly. The maximum deflection of the galvanometer was observed when the magnet was ______.


A coil is connected to a galvanometer. When the N-pole of magnet is pushed into the coil, the galvanometer deflected to the right. What deflection, if any, is observed when: 

 the S-pole is inserted?


In the Activity shown below, how do we think the displacement of rod AB will be affected if

  1. current in rod AB is increased
  2. a stronger horse-shoe magnet is used
  3. length of the rod AB is increased?
  • Take a small aluminium rod AB (of about 5 cm). Using two connecting wires suspend it horizontally from a stand, as shown in Fig.
  • Place a strong horse-shoe magnet in such a way that the rod lies between the two poles with the magnetic field directed upwards. For this put the north pole of the magnet vertically below and south pole vertically above the aluminium rod (Fig.).
  • Connect the aluminium rod in series with a battery, a key and a rheostat.
  • Now pass a current through the aluminium rod from end B to end A.
  • What do you observe? It is observed that the rod is displaced towards the left. You will notice that the rod gets displaced.
  • Reverse the direction of current flowing through the rod and observe the direction of its displacement. It is now towards the right.
  • Why does the rod get displaced?


A current-carrying rod, AB, experiences a force perpendicular to its length and the magnetic field. Support for the magnet is not shown here, for simplicity.


What is the function of a split ring in an electric motor?


When the resistance of a conductor increases, the current ____________ .

(ii) Global warming is a desirable aspect of the intensified greenhouse effect.


Answer the following question:
State the effect on the magnetic needle in Oersted’s experiment when:  
(a) the current is passed through the wire.  
(b) the current through the wire is increased
(c) the current through the wire is reversed. 


Name any two appliances which works on the phenomenon of magnetic effect of electric current.


A uniform magnetic field exists in the plane of paper pointing from left to right as shown in Figure. In the field an electron and a proton move as shown. The electron and the proton experience


Unscramble the following words:

HTRCO


Paheli does not have a night lamp in her room. She covered the bulb of her room with a towel at the night to get dim light. Has she taken the right step? Give one reason to justify your answer.


As shown in the diagram an aluminium rod 'AB' is suspended horizontally between the two poles of a strong horse shoe magnet in such a way that the axis of rod is horizontal and the direction of the magnetic field is vertically upward. The rod is connected in series with a battery and a key.

State giving reason:

  1. What is observed when a current is passed through the aluminium rod from end B to end A?
  2. What change is observed in a situation in which the axis of the rod 'AB' is moved and aligned parallel to the magnetic field and current is passed in the rod in the same direction?

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